Electroformed refractory material, method for producing electroformed refractory material, and glass melting furnace

Abstract

Provided is a electroformed refractory material having a chemical composition comprising, in term of oxides, not less than 85.0 mass% ZrO2, 8.0-12.0 mass% SiO2, not less than 0.10 mass% but less than 0.80 mass% Al2O3, 0.01-1.0 mass% P2O5, 0.10-0.20 mass% of the total of Na2O and / or K2O, and 0.05-2.0 mass% B2O3, where the total of oxides is 100 mass%, and the total amount of Fe2O3 and TiO2 is less than 0.55 mass%. Also provided are a method for producing the electroformed refractory material and a glass melting furnace that uses the electroformed refractory material.

Description

Electrocast refractory, manufacturing method of electrocast refractory, and glass melting furnace

[0001] The present disclosure relates to an electrocast refractory, a method for manufacturing an electrocast refractory, and a glass melting furnace.

[0002] Conventionally, the chemical component is ZrO ２ High-zirconia electrocast refractories containing a large amount of ZrO are known. High-zirconia electrocast refractories have high corrosion resistance and low contamination against molten glass, and are therefore often used in parts that come into contact with molten glass in glass melting furnaces. Such high-zirconia electrocast refractories contain a large amount of zirconia crystal grains and a small amount of matrix glass between the grains. For example, Patent Documents 1 to 9 disclose high-zirconia electrocast refractories containing ZrO ２ High zirconia refractories containing various other components in specific proportions have been proposed.

[0003] Japanese Patent Publication No. 6-287059 Japanese Patent Publication No. 8-277162 Japanese Patent Publication No. 2009-155150 Japanese Patent Publication No. 2010-260782 Japanese Patent Publication No. 2012-518588 Japanese Patent Publication No. 2019-048761 Chinese Patent Application Publication No. 101443290 Chinese Patent Application Publication No. 104583154 Chinese Patent Application Publication No. 113454045

[0004] The electrocast refractory preferably has high electrical resistivity at the temperature at which it is used, from the viewpoint of suppressing the flow of current through the refractory in, for example, a glass melting furnace in which glass is electrically melted.

[0005] Also, ZrO ２ ZrO undergoes transformation expansion due to a phase transition between monoclinic and tetragonal crystals at around 1150°C when heating and at around 850°C when cooling, resulting in a large change in volume as the temperature rises and falls. ２ The matrix glass that fills the gaps is ZrO ２ However, if the volume change during heating and cooling is large, it may cause cracks in the refractory material, so it is desirable to reduce the expansion coefficient after the temperature cycle, i.e., the residual volume expansion coefficient.

[0006] In addition, for example, when a glass melting furnace is used, the matrix glass in the refractory may exude into the molten glass at the contact point between the refractory and the molten glass (also called "glass exudation"). Glass exudation can cause defects in the resulting glass product.

[0007] In view of the above circumstances, the present disclosure relates to an electrocast refractory having high electrical resistivity, low coefficient of permanent volume expansion, and capable of suppressing glass exudation, a method for manufacturing the same, and a glass melting furnace using the electrocast refractory.

[0008] The means for solving the above problems include the following aspects: <1> A chemical composition, based on oxides, where the total amount of oxides is 100 mass %, of ZrO ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10% by mass or more and less than 0.80% by mass, P ２ O ５ 0.01 to 1.0 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 to 0.20 mass%, B ２ O ３ Fe ２ O ３ and TiO ２ <2> The electrocast refractory material, wherein the total amount of the following is less than 0.55% by mass, on an oxide basis, with the total amount of oxides being 100% by mass: Al ２ O ３ 0.10 to 0.70 mass% of P ２ O ５ 0.01 to 0.5 mass% of B ２ O ３ <3> The electrocast refractory according to <1>, containing, on an oxide basis, 0.10 mass % to 1.5 mass % of Al, with the total of the oxides being 100 mass %. ２ O ３ 0.10 to 0.60 mass% of P ２ O ５ 0.01 to 0.3 mass% of B ２ O ３<4> The electrocast refractory material according to <1> or <2>, containing 0.50 mass % to 1.3 mass % of Na. ２ O and / or K ２ <5> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <6> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <7> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <8> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <9> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <10> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <11> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <12> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <13> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <14> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <15> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. <16> The electrocast refractory according to any one of <1> to <3>, containing 0.11 to 0.20 mass% of O in total. ２ O ３ and TiO ２ <6> The electrocast refractory material according to any one of <1> to <4>, wherein the total amount of Na is 0.30 mass% or less. ２ O and K ２ The total mass of O is SiO ２ <7> The electrocast refractory material according to any one of <1> to <5>, wherein a value obtained by dividing the above by the mass of B is 0.01 or more. ２ O ３ and P ２ O ５ The total mass of Al ２ O ３ <1> The electrocast refractory according to any one of <1> to <6>, wherein a value obtained by dividing the coefficient of electrical expansion by the mass of the electrocast refractory is 1.0 or more. <8> The electrocast refractory according to any one of <1> to <7>, wherein the electrical resistivity at 1600°C is 300 Ω cm or more. <9> The electrocast refractory according to any one of <1> to <8>, wherein the electrical resistivity at 1600°C is 400 Ω cm or more. <10> The electrocast refractory according to any one of <1> to <9>, wherein the electrocast refractory is subjected to a thermal cycle test in which the electrocast refractory is heated from 800°C to 1250°C at a rate of 450°C / h and then cooled from 1250°C to 800°C at a rate of 450°C / h, repeated 40 times, and after that, the electrocast refractory has a residual volume expansion coefficient calculated by the following formula of 10% or less: Residual volume expansion coefficient (%) = {(volume after thermal cycle test / volume before thermal cycle test) - 1} x 100. <11> A glass melting furnace comprising the electrocast refractory material according to any one of <1> to <10>. <12> A glass melting furnace comprising: a refractory material containing ZrO relative to the total mass of oxides; ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10% by mass or more and less than 0.80% by mass, P ２ O ５0.01 to 1.0 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 to 0.20 mass%, B ２ O ３ 0.05 mass % to 2.0 mass % of Fe ２ O ３ and TiO ２ a refractory raw material having a total content of less than 0.55 mass % and a total content of less than 0.55 mass %, and then the refractory raw material is cooled in a mold.

[0009] According to the present disclosure, there are provided an electrocast refractory having high electrical resistivity, low coefficient of permanent volume expansion, and suppressed glass exudation, a method for manufacturing the same, and a glass melting furnace using the electrocast refractory.

[0010] Hereinafter, modes for carrying out embodiments of the present disclosure will be described in detail. However, the embodiments of the present disclosure are not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and they do not limit the embodiments of the present disclosure.

[0011] In the present disclosure, a numerical range indicated using "to" includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the present disclosure, each component may contain multiple corresponding substances. When multiple substances corresponding to each component are present in the composition, the content or amount of each component means the total content or amount of the multiple substances present in the composition, unless otherwise specified. In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.

[0012] <Electrocast Refractory> The electrocast refractory of the present disclosure (hereinafter also simply referred to as "refractory") has a chemical composition, on an oxide basis, where the total amount of oxides is 100 mass %, of ZrO ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10% by mass or more and less than 0.80% by mass, P ２ O ５0.01 to 1.0 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 to 0.20 mass%, B ２ O ３ Fe ２ O ３ and TiO ２ The total amount of is less than 0.55 mass%.

[0013] The inventors have found that a refractory material having the above composition has high electrical resistivity, low coefficient of permanent volume expansion, and can suppress glass exudation. The reason for this is not entirely clear, but is presumed to be as follows. In the refractory material of the present disclosure, Al ２ O ３ The content of Al is suppressed to less than 0.80 mass%. ２ O ３ By suppressing the amount of ZrO within the above range, ２ It is believed that the electrical resistivity of the matrix glass is improved. ２ P, which forms a glass phase similarly to ２ O ５ and B ２ O ３ By adjusting the viscosity of the matrix glass, Na has the effect of preventing cracks from occurring during manufacturing and improving or suppressing a decrease in electrical resistivity. ２ O and K ２ The total amount of O is suppressed to 0.20 mass % or less. ２ O and K ２ O is present in the matrix glass, and by limiting the total amount to 0.20 mass % or less, a decrease in electrical resistivity is suppressed. ２ O and / or K ２ O makes it easier to melt the raw materials. ２ O and / or K ２ O is present in the matrix glass and contributes to lowering the viscosity of the matrix glass. ２ O and / or K ２By containing 0.10 mass % or more of O in total, it is believed that good electrical resistivity is ensured, poor melting of the refractory material is reduced, and expansion caused by zirconia transformation during slow cooling can be absorbed, resulting in a dense brick, which in turn suppresses the residual volume expansion rate and glass exudation. ２ is the main component of the matrix glass, and ZrO ２ In addition, in the refractory material of the present disclosure, B contributes to absorbing the stress of the volume change and suppresses the residual volume expansion rate. ２ O ３ The fact that the content of Fe is kept to 2.0 mass % or less also contributes to the suppression of the coefficient of permanent volume expansion. ２ O ３ and TiO ２ However, in the refractory material of the present disclosure, the amounts of these components are suppressed, so that the effects of the above components can be exhibited well. ２ , SiO ２ , Al ２ O ３ , P ２ O ５ , Na ２ O and / or K ２ O, B ２ O ３ , and Fe ２ O ３ and TiO ２ When the content ratio of is within a specific range, a refractory having high electrical resistivity, low coefficient of permanent volume expansion, and suppressed glass exudation can be obtained. ２ O and / or K ２ It is preferable that the content of O is kept low in order to increase the electrical resistivity. ２ O and / or K ２ If the O content is low, the densification of the refractory structure decreases, making it difficult to suppress the coefficient of permanent volume expansion and glass exudation. As such, maintaining or improving electrical resistivity and suppressing the coefficient of permanent volume expansion and glass exudation tend to be in a trade-off relationship, making it difficult to achieve both. In the refractory of the present disclosure, it is believed that the actions of the above components in specific proportions work together to achieve both of these properties. Note that the embodiments of the present disclosure are in no way limited by the above-mentioned assumed mechanism.

[0014] In the present disclosure, unless otherwise specified, the content or amount of a component of a refractory expressed in mass% indicates the content or amount of the component on an oxide basis when the total amount of oxides in the refractory is taken as 100 mass% as the chemical composition. The chemical composition in a refractory is, in principle, a quantitative analysis value determined by wavelength dispersive X-ray fluorescence spectrometry, and B ２ O ３ is a quantitative analysis value determined by high frequency inductively coupled plasma atomic emission spectrometry, and Na ２ O and K ２ ZrO is a quantitative value determined by atomic absorption spectrometry. ２ The content of ZrO is calculated from the mass of the refractory. ２ It is calculated by subtracting the mass of the components other than

[0015] The refractory is ZrO ２ Contains 85.0 mass % or more of ZrO ２ From the viewpoint of further increasing the corrosion resistance of the refractory material to molten glass, ZrO ２ The content of ZrO is preferably 85.5% by mass or more, and more preferably 86.0% by mass or more. ２ From the viewpoint of suppressing the occurrence of cracks due to volume changes, ZrO ２ The content of ZrO is preferably 91.5% by mass or less, more preferably 91.0% by mass or less, and even more preferably 90.0% by mass or less. ２ The content is preferably 85.0 to 91.5 mass%, more preferably 85.5 to 91.0 mass%, and even more preferably 86.0 to 90.0 mass%.

[0016] In addition, in the refractory material using the zirconia source, ZrO ２ Inevitably, a small amount (generally about 2 mass % or less) of HfO ２ HfO is mixed. ２ is ZrO ２ To play the same role as ２ and ZrO ２ The sum of these values ​​is generally ZrO ２ In this disclosure, for clarity, HfO ２ ZrO mixed with ２(i.e., ZrO ２ and HfO ２ The mixture of ZrO ２ " or "zirconia." That is, "ZrO ２ " or "zirconia" means ZrO unless otherwise specified. ２ HfO mixed with ２ For example, if the refractory is "ZrO ２ "Contains 85.0 mass % or more of ZrO ２ HfO mixed with ２ This means that the total amount of is 85.0 mass % or more.

[0017] The refractory material is SiO ２ Contains 8.0 to 12.0 mass % of SiO ２ is a component that forms the matrix glass. ２ By containing 8.0 mass% or more of ZrO ２ From the viewpoint of further suppressing the volume change, further improving the electrical resistivity, and further achieving both of the above advantages, SiO ２ The content of SiO is preferably 8.5% by mass or more, more preferably 9.0% by mass or more, more preferably 9.5% by mass or more, and even more preferably 10.0% by mass or more. ２ The content of SiO is preferably less than 12.0% by mass, more preferably 11.5% by mass or less, and even more preferably 11.0% by mass or less. ２ The content is preferably 8.5 to 11.5 mass%, more preferably 9.0 to 11.0 mass%, and even more preferably 10.0 to 11.0 mass%.

[0018] The refractory is Al ２ O ３ The refractory contains 0.10 mass % or more and less than 0.80 mass % of Al. ２ O ３It is believed that by containing 0.10 mass % or more of Al, the viscosity of the matrix glass can be suppressed, and the occurrence of cracks can be suppressed. In addition, when a part of the matrix glass reacts with zirconia crystals, zircon is generated, which reduces the amount of matrix glass and makes it difficult for the matrix glass to perform its function. ２ O ３ It is believed that the inclusion of Al can also suppress the generation of zircon. ２ O ３ The content of Al in the refractory material may be 0.20% by mass or more, 0.30% by mass or more, 0.40% by mass or more, or 0.45% by mass or more. ２ O ３ It has been found that the electrical resistivity of the refractory material is increased by suppressing the Al content in the refractory material to less than 0.80 mass%. ２ O ３ By reducing the content of Al, it is possible to prevent aluminosilicate crystals such as mullite from being generated during the manufacture or use of the refractory material, which may cause cracks. ２ O ３ The content of Al is preferably 0.70 mass% or less, and more preferably 0.60 mass% or less. ２ O ３ The content is preferably 0.10 to 0.70 mass %, more preferably 0.10 to 0.60 mass %.

[0019] The refractory material is P ２ O ５ Contains 0.01 to 1.0 mass % of P ２ O ５ contributes to the improvement of the electrical resistivity. ２ O ５ The content of P may be 0.03% by mass or more, 0.07% by mass or more, or 0.1% by mass or more. From the viewpoint of suppressing the generation of zircon and suppressing residual expansion and chip-off, in which the surface of the refractory material is partially chipped off during heating, P ２ O ５The content of P is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. ２ O ５ The content is preferably 0.01 to 0.5 mass %, more preferably 0.01 to 0.3 mass %.

[0020] The refractory is Na ２ O and / or K ２ Contains a total of 0.10 to 0.20 mass% of O. ２ O and K ２ O is present in the matrix glass, and by making the total amount 0.20 mass % or less, a decrease in electrical resistivity is suppressed. In addition, from the viewpoint of achieving suppression of the residual volume expansion coefficient, suppression of cracks, and suppression of glass exudation due to the improvement in the density of the refractory structure that is manifested as a result of suppression of zircon formation and improvement of meltability while ensuring a desired electrical resistivity, Na ２ O and / or K ２ The total amount of O is 0.10% by mass or more, may be more than 0.10% by mass, may be 0.11% by mass or more, may be 0.12% by mass or more, or may be 0.13% by mass or more. ２ O and / or K ２ The total amount of O is 0.20% by mass or less, preferably 0.19% by mass or less, may be 0.18% by mass or less, may be 0.17% by mass or less, may be 0.16% by mass or less, or may be 0.15% by mass or less. ２ O and / or K ２ The total amount of O is preferably more than 0.10 mass% but not more than 0.20 mass%, more preferably 0.11 to 0.20 mass%, and particularly preferably 0.11 to 0.15 mass%. ２ O and K ２ O may be contained in either one of the two or in both of them. ２ O and K ２ The content of O is independently 0.10 to 0.20 mass%, preferably more than 0.10 mass% and not more than 0.18 mass%, more preferably 0.11 to 0.15 mass%, provided that the total content of Na is 0.10 to 0.20 mass%. ２ O and K２ Among O, K ２ It is preferable that O is contained in a larger amount. ２ O and K ２ In the case of O, due to the difference in ionic radius, Na ２ This is because O has a higher ionic conductivity, and the higher the ionic conductivity, the lower the electrical resistance tends to be. ２ It is preferable that the content of O is large.

[0021] Refractories are B ２ O ３ The refractory material contains 0.05 mass % to 2.0 mass % of B. ２ O ３ The inclusion of 0.05 mass % or more of B has the effect of suppressing crack generation during manufacturing. ２ O ３ P ２ O ５ By including both, the viscosity of the matrix glass is reduced, and the occurrence of cracks can be suppressed. ２ O ３ As the content of Na increases, the electrical resistivity ２ O and K ２ It is difficult to decrease compared with alkali metal oxides such as O. From the above viewpoint, B ２ O ３ The content of B is preferably 0.10% by mass or more, more preferably 0.50% by mass or more, and even more preferably 0.60% by mass or more. ２ O ３ The content of B is preferably 1.5% by mass or less, and more preferably 1.0% by mass or less. ２ O ３ The content is preferably 0.10 to 2.0 mass %, more preferably 0.50 to 1.0 mass %.

[0022] Fe in refractories ２ O ３ and TiO ２ The total amount of Fe is less than 0.55% by mass. ２ O ３ and TiO ２is an impurity that may be mixed in from the raw materials and reduces the electrical resistivity, so it is preferable to have a small amount. In addition, from the viewpoint of suppressing the cause of peeling due to the expansion of the reaction product of iron and phosphorus at high temperatures, Fe ２ O ３ In addition, from the viewpoint of suppressing the residual volume expansion coefficient, the amount of TiO ２ From the above viewpoint, the amount of Fe is preferably small. ２ O ３ and TiO ２ The total amount of is preferably 0.40 mass% or less, more preferably 0.30 mass% or less. ２ O ３ and TiO ２ Either one, both, or neither may be contained. The amount of each is 0.55% by mass or less, preferably 0.40% by mass or less, and more preferably 0.30% by mass or less.

[0023] In refractories, Na ２ O and K ２ The total mass of O is SiO ２ From the viewpoints of improving the density of the refractory structure, suppressing the coefficient of permanent volume expansion, suppressing cracking, and suppressing glass exudation, the value obtained by dividing by the mass of the refractory is preferably 0.01 or more (or 0.010 or more), and more preferably 0.011 or more. From the viewpoint of improving the electrical resistivity, the value is preferably 0.020 or less, preferably 0.017 or less, more preferably 0.015 or less, and even more preferably 0.013 or less. From the above viewpoints, the value is preferably 0.010 to 0.020, and more preferably 0.010 to 0.013.

[0024] In refractories, B ２ O ３ and P ２ O ５ The total mass of Al ２ O ３ The value obtained by dividing by the mass of Al is preferably 1.0 or more (or 1.00 or more), more preferably 1.3 or more (or 1.30 or more), may be 1.4 or more (or 1.40 or more), or may be 1.5 or more (or 1.50 or more). ２ O ３ Reduction in the amount of P２ O ５ The addition of B contributes to the improvement of electrical resistivity. ２ O ３ contributes to crack suppression. In order to obtain a refractory material having high electrical resistivity and free from cracks during production, it is preferable that this parameter be in the above range. It is believed that when the value is 1.0 or more, the electrical resistivity is particularly improved. From the viewpoint of the residual expansion coefficient, the upper limit of the value is preferably 3.0 or less (or 3.00 or less), more preferably 2.5 or less (or 2.50 or less), and even more preferably 2.0 or less (or 2.00 or less). From the above viewpoints, the value is preferably 1.0 to 3.0 (or 1.00 to 3.00), more preferably 1.3 to 3.0 (or 1.30 to 3.00), even more preferably 1.4 to 2.5 (or 1.40 to 2.50), and particularly preferably 1.5 to 2.0 (or 1.50 to 2.00).

[0025] The refractory material contains the above-mentioned components (i.e., ZrO ２ , SiO ２ , Al ２ O ３ , P ２ O ５ , Na ２ O.K. ２ O, B ２ O ３ , Fe ２ O ３ , TiO ２ The components derived from raw materials other than the above-mentioned components may or may not be contained independently. ２ O ３ In the refractory material, the above-mentioned components (i.e., ZrO ２ , SiO ２ , Al ２ O ３ , P ２ O ５ , Na ２ O.K. ２ O, B ２ O ３The total amount of components other than the above is preferably 0.7% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.4% by mass or less, particularly preferably 0.2% by mass or less, extremely preferably 0.1% by mass or less, even more preferably less than 0.1% by mass, and even more preferably 0.05% by mass or less.

[0026] For example, CuO may be contained as an impurity in refractory raw materials. ２ O ５ and / or B ２ O ３ From the viewpoint of suppressing deterioration in durability when CuO is simultaneously contained, the amount of CuO is preferably small, and the amount of CuO is preferably 0.1 mass % or less, more preferably 0.05 mass % or less, and even more preferably 0.01 mass % or less.

[0027] In addition, MgO and CaO may also be contained as impurities in the refractory raw material. From the viewpoint of suppressing a decrease in the electrical resistance efficiency, the amounts of MgO and CaO are preferably small, and each independently is preferably 0.1 mass% or less, and more preferably 0.05 mass% or less.

[0028] Similarly, Y ２ O ３ In order to prevent the decrease in the electrical resistance efficiency, Y ２ O ３ The amount is preferably small, preferably 0.3 mass % or less, more preferably 0.2 mass % or less.

[0029] The refractory material of the present disclosure is, for example, V described in Patent Documents 7 and 8. ２ O ５ , CrO ３ , Nb ２ O ５ , MoO ３ , Ta ２ O ５ , W.O. ３ , SnO ２ High electrical resistivity, low coefficient of permanent volume expansion, and suppression of glass exudation can be achieved without intentionally adding components such as V. ２ O ５ , CrO ３ , Nb２ O ５ , MoO ３ , Ta ２ O ５ , W.O. ３ , SnO ２ The total mass of the oxides may be less than 0.01 mass % or 0.005 mass % or less, with the total of the oxides being 100 mass %.

[0030] The refractory preferably has a chemical composition, on an oxide basis, where the total of the oxides is 100 mass %, of Al ２ O ３ 0.10 to 0.70 mass% of P ２ O ５ 0.01 to 0.5 mass% of B ２ O ３ Contains 0.10 mass % to 1.5 mass % of

[0031] The refractory more preferably has a chemical composition, on an oxide basis, where the total of the oxides is 100 mass %, of Al ２ O ３ 0.10 to 0.60 mass% of P ２ O ５ 0.01 to 0.3 mass% of B ２ O ３ Contains 0.50 mass % to 1.3 mass % of

[0032] The refractory preferably has a chemical composition, on an oxide basis, where the total of the oxides is 100 mass %, of ZrO ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10 to 0.65 mass% P ２ O ５ 0.01 to 0.15 mass% B ２ O ３ Fe ２ O ３ and TiO ２ The total amount of is 0.30 mass % or less.

[0033] [Method for producing refractory] The refractory can be produced by heating and melting refractory raw materials and cooling them in a mold. In one embodiment of the present disclosure, the method for producing the refractory includes the steps of: ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10% by mass or more and less than 0.80% by mass, P ２ O ５ 0.01 to 1.0 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 mass % to 0.20 mass %, B ２ O ３ 0.05 mass % to 2.0 mass % of Fe ２ O ３ and TiO ２ The method includes heating and melting a refractory raw material having a total content of less than 0.55 mass %, and then cooling it in a mold. The details of each component contained in the refractory raw material are as described above.

[0034] Specifically, the refractory is produced by, for example, mixing powder raw materials so as to obtain the above-mentioned blending ratio, melting the mixed raw materials in an electric arc furnace, and then forcing the molten raw materials into a graphite mold and cooling the mixture. ２ The powder tends to have excellent corrosion resistance due to its dense crystalline structure and large crystal size. Heating during melting is carried out, for example, by bringing the raw material powder into contact with a graphite electrode and passing an electric current through the electrode.

[0035] [Characteristics of Refractory] The electrical resistivity of the refractory at 1600°C is preferably 300 Ω cm or more, more preferably 350 Ω cm or more, even more preferably 400 Ω cm or more, and particularly preferably 450 Ω cm or more. The upper limit of the electrical resistivity is not particularly limited, and may be, for example, 1000 Ω cm. The electrical resistivity is measured using an AC voltage of 120 Hz using a three-terminal electrode configuration equipped with a guard electrode.

[0036] The refractory preferably has a permanent volume expansion coefficient of 10% or less, more preferably 8% or less, even more preferably 6% or less, and particularly preferably 4% or less, as determined below. A thermal cycle test is conducted on the refractory, in which the temperature is increased from 800°C to 1250°C at a rate of 450°C / h and then decreased from 1250°C to 800°C at a rate of 450°C / h, and this cycle is repeated 40 times. The heating from room temperature (about 25°C) to 800°C and the cooling from 800°C to room temperature (about 25°C) are performed at a rate of about 160°C / h. The permanent volume expansion coefficient is determined by the following formula: Permanent volume expansion coefficient (%) = {(Volume after thermal cycle test / Volume before thermal cycle test) - 1} x 100

[0037] The bulk density of the refractory material is 4.7 g / cm from the viewpoint of density and corrosion resistance to molten glass. ３ More preferably, 4.8 g / cm ３ More preferably, 4.9 g / cm ３ The above is more preferable. The bulk specific gravity is measured by the Archimedes method.

[0038] The porosity of the refractory is preferably 1.5% or less. When the porosity of the refractory is low, the corrosion resistance against molten glass is increased. The porosity is more preferably 0.1 to 1%. The porosity is measured by Archimedes' method.

[0039] The mass of the refractory is preferably 200 kg or more. The refractory preferably has a low residual volume expansion coefficient and can suppress the occurrence of cracks even when producing a large refractory. The mass of the refractory is more preferably 400 to 1500 kg.

[0040] [Uses of Refractories] Refractories are preferably used, for example, as materials for glass melting furnaces. Glass melting furnaces are used to produce glass products such as plate glass. In particular, refractories are preferably used in areas of the glass melting furnace that come into contact with molten glass. The refractory material of the present disclosure has high electrical resistivity, and is therefore particularly preferably used, for example, in areas where electrodes are installed in the glass melting furnace and around those areas.

[0041] Therefore, in one embodiment of the present disclosure, a glass melting furnace includes the refractory of the present disclosure. In particular, it is preferable to use the refractory of the present disclosure in a portion of the glass melting furnace that comes into contact with molten glass, for example, in and around an electrode installation portion.

[0042] Next, embodiments of the present disclosure will be described in detail using examples, but the embodiments of the present disclosure are not limited to these examples. Examples 1 to 5, 10 to 12, and 15 are comparative examples, and Examples 6 to 9, 13, and 14 are working examples.

[0043] <Production of Refractories> A refractory raw material was obtained by mixing desiliconized zirconia, alumina, zircon sand, silica, sodium carbonate, potassium carbonate, boron phosphate, and boron oxide as raw materials. The refractory raw material was melted by electrical heating using the so-called arc method, in which a graphite electrode was raised above the molten metal surface. The molten refractory raw material was cast by pouring it into a graphite mold previously embedded in Bayer alumina or silica sand as an annealing material, and allowed to cool to a temperature near room temperature (approximately 25°C). The molds were fabricated to obtain rectangular refractories measuring 130 mm x 160 mm x 300 mm in Examples 1 to 7 and 10 to 15, and 125 mm x 575 mm x 950 mm in Examples 8 and 9. After casting and cooling, the ingot and graphite mold were removed from the annealing material, and the graphite mold and ingot were separated to obtain a refractory.

[0044] The component compositions of the refractories of Examples 1 to 15 obtained by adjusting the raw material composition are shown in Tables 1 and 2. The chemical compositions are, in principle, quantitative analytical values ​​determined by wavelength dispersive X-ray fluorescence analysis. ２ O ３ is a quantitative analysis value determined by high frequency inductively coupled plasma atomic emission spectrometry, and Na ２ O and K ２ ZrO is a quantitative value determined by atomic absorption spectrometry. ２ The content of ZrO is calculated from the mass of the refractory. ２ It is calculated by subtracting the mass of the components other than

[0045] <Evaluation> [Residual volume expansion coefficient] A cylindrical sample measuring 35 mm in diameter x 40 mm was cut out from the manufactured refractory material. A thermal cycle test was carried out in an electric furnace, in which the refractory material was heated from 800°C to 1250°C at a rate of 450°C / h and cooled from 1250°C to 800°C at a rate of 450°C / h, with this cycle repeated 40 times. The heating from room temperature (about 25°C) to 800°C and the cooling from 800°C to room temperature (about 25°C) were carried out at a rate of about 160°C / h. The residual volume expansion coefficient was calculated using the following formula: Residual volume expansion coefficient (%) = {(volume after thermal cycle test / volume before thermal cycle test) - 1} x 100

[0046] [Glass exudation] Cylindrical samples with a diameter of 30 mm and a height of 30 mm were cut out using a diamond core drill, and fired in an electric furnace at 1500°C for 16 hours, and then allowed to cool naturally within the furnace. The samples were visually inspected for the presence or absence of glass exudation before and after firing.

[0047] [Electrical Resistivity] A disk-shaped sample with a diameter of 20 mm and a thickness of 3 mm was cut out from the refractory material. A main electrode and a guard electrode were attached to one side of the sample, and only a counter electrode was attached to the other side using platinum paste. Platinum electrodes for measuring the electrical resistivity of the sample were set inside an electric furnace capable of heating up to a maximum temperature of 1650°C, and the sample was then placed in the electric furnace. While heating at a rate of 5°C / min, the volume resistivity was continuously measured using an insulation resistance measuring device while applying an AC voltage with a frequency of 120 Hz. The volume resistivity (Ω cm) was calculated from the obtained volume resistance.

[0048] In Tables 1 and 2, the component composition is expressed as the proportion (mass%) of each component on an oxide basis, with the total oxide amount being 100 mass%. A "-" in the component composition indicates that the corresponding component was not detected, and a "-" in the evaluation indicates that the corresponding evaluation was not performed or could not be measured. "Na ２ O+K ２ "O" is Na ２ O and K ２ represents the total proportion (mass%) of O, and "Fe ２ O ３ + TiO ２ " is Fe ２ O ３ and TiO ２represents the total proportion (mass%) of ２ O+K ２ O) / SiO ２ " is Na ２ O and K ２ The total mass of O is SiO ２ represents the value divided by the mass of "(B ２ O ３ +P ２ O ５ ) / Al ２ O ３ " is B ２ O ３ and P ２ O ５ The total mass of Al ２ O ３ The values ​​in parentheses in the table are values ​​with one decimal place added.

[0049]

[0050]

[0051] In both examples, V ２ O ５ , CrO ３ , Nb ２ O ５ , MoO ３ , Ta ２ O ５ , W.O. ３ , and SnO ２ The total mass of the oxides was less than 0.01% by mass, with the total mass of the oxides being 100% by mass.

[0052] Na ２ O and K ２ The refractory material of Example 1, in which the total proportion of O was low, had a high coefficient of residual volume expansion. ２ O and K ２ In the refractory material of Example 2, which had a low total ratio of O, the coefficient of permanent volume expansion was high and glass exudation was observed after firing. ２ O and K ２ In the refractory of Example 3, which had a low total proportion of O, glass exudation was observed after firing. ２ O and K ２In the refractory of Example 4, which had a low total proportion of O, glass exudation was observed after firing. This is thought to be due in part to the low alkali proportion and insufficient density of the refractory structure. Note that in Examples 2 to 4, in which glass exudation was observed, electrical resistivity was not evaluated because it would lead to equipment failure. ２ O ３ The refractory material of Example 5, which had a high ratio of , had a low electrical resistivity.

[0053] In Example 10, P ２ O ５ The proportion of Na is low ２ O and K ２ In Example 11, the total proportion of B was high, and a high coefficient of permanent volume expansion and a low electrical resistivity were observed. ２ O ３ In Example 12, the proportion of Na was high, the residual volume expansion coefficient was high, and glass exudation was observed. ２ O and K ２ In Example 15, the total proportion of SiO was high and the electrical resistivity was low. ２ The proportion of Na is low ２ O and K ２ The total percentage of O was low, and the volume expansion was large, so the residual volume expansion rate could not be measured. Glass exudation was also observed. Furthermore, the electrical resistivity was high.

[0054] The refractories of Examples 6 to 9, 13, and 14 had high electrical resistivity, low coefficient of permanent volume expansion, and no glass exudation was observed. ２ O ５ The refractory material of Example 9, which had a high content of , exhibited a particularly high electrical resistivity.

[0055] From the above results, it can be seen that the refractory material of the present disclosure has high electrical resistivity, low coefficient of permanent volume expansion, and suppresses glass exudation.

[0056] (Additional Notes) The present disclosure includes the following aspects: <1> A chemical composition based on oxides, with the total amount of oxides being 100 mass %, of ZrO ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３0.10% by mass or more and less than 0.80% by mass, P ２ O ５ 0.01 to 1.0 mass% of Na ２ O and / or K ２ O: 0.10 to 1.0 mass% in total; B: ２ O ３ Fe in an amount of 0.05 to 3.0 mass % ２ O ３ and TiO ２ <2> The electrocast refractory material, wherein the total amount of the following is less than 0.55% by mass, on an oxide basis, with the total amount of oxides being 100% by mass: Al ２ O ３ 0.10 to 0.70 mass% of P ２ O ５ 0.01 to 0.5 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 to 0.50 mass%, B ２ O ３ <3> The electrocast refractory material according to <1>, containing, on an oxide basis, 0.10 mass % to 2.0 mass % of Al, with the total of the oxides being 100 mass %. ２ O ３ 0.10 to 0.60 mass% of P ２ O ５ 0.01 to 0.3 mass% of Na ２ O and / or K ２ O in a total amount of 0.10 to 0.30 mass%, B ２ O ３ <4> The electrocast refractory material according to <1> or <2>, containing, on an oxide basis, 0.50 mass % to 1.0 mass % of Fe, ２ O ３ and TiO ２ <5> The electrocast refractory material according to any one of <1> to <3>, wherein the total amount of Na is 0.30 mass% or less. ２ O and K ２ The total mass of O is SiO ２ <6> The electrocast refractory material according to any one of <1> to <4>, wherein a value obtained by dividing the above by the mass of B is 0.01 or more. ２ O ３ and P ２ O５ The total mass of Al ２ O ３ <1> <5> The electrocast refractory according to any one of <1> to <5>, having a value obtained by dividing the coefficient of electrical expansion by the mass of the electrocast refractory by the mass of the refractory of 1.3 or more. <7> The electrocast refractory according to any one of <1> to <6>, having an electrical resistivity of 350 Ω cm or more at 1600°C. <8> The electrocast refractory according to any one of <1> to <7>, having an electrical resistivity of 400 Ω cm or more at 1600°C. <9> The electrocast refractory according to any one of <1> to <8>, having a residual volume expansion coefficient calculated by the following formula of 10% or less after a thermal cycle test in which the electrocast refractory is subjected to 40 cycles of increasing the temperature from 800°C to 1250°C at a rate of 450°C / h and decreasing the temperature from 1250°C to 800°C at a rate of 450°C / h: Residual volume expansion coefficient (%) = {(volume after thermal cycle test / volume before thermal cycle test) - 1} x 100. <10> A glass melting furnace comprising the electrocast refractory material according to any one of <1> to <9>. <11> A glass melting furnace comprising an electrocast refractory material according to any one of <1> to <9>, wherein: <12> a content of ZrO relative to the total mass of oxides is 100% or more; ２ 85.0 mass% or more of SiO ２ 8.0 to 12.0 mass% of Al ２ O ３ 0.10% by mass or more and less than 0.80% by mass, P ２ O ５ 0.01 to 1.0 mass% of Na ２ O and / or K ２ O is 0.10 mass % to 1.0 mass % in total, B ２ O ３ Fe in an amount of 0.05 mass % to 3.0 mass % ２ O ３ and TiO ２ a refractory raw material having a total content of less than 0.55 mass % and a total content of less than 0.55 mass %, and then the refractory raw material is cooled in a mold.

[0057] The disclosure of Japanese Patent Application No. 2024-006270, filed on January 18, 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. In terms of chemical composition, on an oxide basis, with the total of oxides being 100% by mass, ZrO ２ is 85.0% by mass or more, SiO ２ is 8.0 to 12.0% by mass, Al ２ O ３ is 0.10% by mass or more and less than 0.80% by mass, P ２ O ５ is 0.01 to 1.0% by mass, Na ２ O and / or K ２ O has a total of 0.10 to 0.20% by mass, B ２ O ３ is 0.05 to 2.0% by mass, and the total amount of Fe ２ O ３ and TiO ２ is less than 0.55% by mass, an electroforming refractory.

2. In terms of chemical composition, on an oxide basis, with the total of the oxides being 100% by mass, Al ２ O ３ is 0.10 to 0.70% by mass, P ２ O ５ is 0.01 to 0.5% by mass, B ２ O ３ is contained in an amount of 0.10% to 1.5% by mass, the electroforming refractory according to claim 1.

3. In terms of chemical composition, on an oxide basis, with the total of the oxides being 100% by mass, Al ２ O ３ is 0.10 to 0.60% by mass, P ２ O ５ is 0.01 to 0.3% by mass, B ２ O ３ is contained in an amount of 0.50% to 1.3% by mass, the electroforming refractory according to claim 1.

4. Na ２ O and / or K ２ The electroforming refractory according to claim 1, containing a total of 0.11 to 0.20% by mass of O and / or K 5. In terms of chemical composition, on an oxide basis, with the total of oxides being 100% by mass, the total amount of Fe ２ O ３ and TiO ２ is 0.30% by mass or less. The electroformed refractory according to claim 1.

6. Na ２ O and K ２ The value obtained by dividing the total mass of O by the mass of SiO ２ is 0.01 or more. The electroformed refractory according to claim 1.

7. B ２ O ３ and P ２ O ５ The value obtained by dividing the total mass of ２ O ３ by the mass of Al ２ O ３ is 1.0 or more. The electroformed refractory according to claim 1.

8. The electroformed refractory according to claim 1, having an electrical resistivity of 300 Ω·cm or more at 1600°C.

9. The electroformed refractory according to claim 1, having an electrical resistivity of 400 Ω·cm or more at 1600°C.

10. After performing a thermal cycle test in which the temperature of the electroformed refractory is raised from 800°C to 1250°C at 450°C / h and then lowered from 1250°C to 800°C at 450°C / h, and repeating this cycle 40 times, the residual volume expansion rate obtained by the following formula is 10% or less. Residual volume expansion rate (%) = { (volume after thermal cycle test / volume before thermal cycle test) - 1} × 100. The electroformed refractory according to claim 1.

11. A glass melting furnace comprising the electroformed refractory according to any one of claims 1 to 10.

12. Based on the total mass of the oxide, ZrO ２ is 85.0% by mass or more, SiO ２ is 8.0 to 12.0% by mass, Al ２ O ３ is 0.10% by mass or more and less than 0.80% by mass, P ２ O ５ is 0.01 to 1.0% by mass, Na ２ O and / or K ２ O has a total of 0.10% by mass to 0.20% by mass, B ２ O ３ is 0.05% by mass to 2.0% by mass, and after heating and melting a refractory raw material containing a total amount of Fe ２ O ３ and TiO ２ less than 0.55% by mass, it is cooled in a mold. A method for manufacturing an electroformed refractory.

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