WO2023190806A1 - Magnesium oxide for annealing separating agent, and grain-oriented electrical steel sheet - Google Patents

Magnesium oxide for annealing separating agent, and grain-oriented electrical steel sheet Download PDF

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WO2023190806A1
WO2023190806A1 PCT/JP2023/013053 JP2023013053W WO2023190806A1 WO 2023190806 A1 WO2023190806 A1 WO 2023190806A1 JP 2023013053 W JP2023013053 W JP 2023013053W WO 2023190806 A1 WO2023190806 A1 WO 2023190806A1
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magnesium oxide
less
pore
film
annealing separator
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PCT/JP2023/013053
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French (fr)
Japanese (ja)
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宙宜 芝田
啓祐 塘
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タテホ化学工業株式会社
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01FCOMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00Compounds of magnesium
    • C01F5/02Magnesia
    • C01F5/06Magnesia by thermal decomposition of magnesium compounds
    • C01F5/08Magnesia by thermal decomposition of magnesium compounds by calcining magnesium hydroxide
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/12Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/20Recycling

Definitions

  • the present invention relates to magnesium oxide (MgO) for use as an annealing separator and grain-oriented electrical steel sheets.
  • MgO magnesium oxide
  • Grain-oriented electrical steel sheets used in transformers and generators are generally made of silicon steel containing about 3% silicon (Si), which is hot-rolled, then cold-rolled to the final thickness, and then decarburized and annealed. , finished annealing, and manufactured.
  • decarburization annealing primary recrystallization annealing
  • a SiO 2 film is formed on the surface of the steel sheet, a slurry containing magnesium oxide for an annealing separation agent is applied to the surface, dried, wound into a coil shape, and then final annealed.
  • SiO 2 and MgO react to form a forsterite (Mg 2 SiO 4 ) film on the surface of the steel plate.
  • This forsterite coating serves to add tension to the surface of the steel sheet, reduce iron loss, improve magnetic properties, and provide insulation to the steel sheet.
  • This forsterite film determines the product's appearance and electrical insulation, and also influences its market value.
  • the film formation process affects the inhibitor decomposition behavior of the surface layer of the steel sheet, and ultimately the secondary recrystallization, and the quality of the film affects the quality of the magnetic properties of the product.
  • the appearance of the coating influences the final appearance of the grain-oriented electrical steel sheet as a product. Therefore, the appearance of the coating has an impact on the product value and has a large effect on the product yield, and if the coating is non-uniform, the manufacturing yield of the product will be reduced. Therefore, improving the properties of such coatings plays an important role in the manufacturing technology of grain-oriented electrical steel sheets.
  • magnesium oxide as an annealing separator
  • various efforts have been made to improve quality.
  • Various studies have been made on the powder characteristics of magnesium oxide for use as an annealing separator, such as the concentration of impurities such as Cl, citric acid activity (CAA), BET specific surface area, and particle size distribution.
  • concentration of impurities such as Cl, citric acid activity (CAA), BET specific surface area, and particle size distribution.
  • Patent Document 1 discloses a technique for improving the magnetic properties and coating properties of a grain-oriented electrical steel sheet by setting the distribution of N2 gas adsorption isotherms and water vapor adsorption isotherms of magnesium oxide particles to a specific range.
  • Patent Document 2 discloses a technique for improving the magnetic properties and coating properties of grain-oriented electrical steel sheets by controlling the pore volume of magnesium oxide particles within a specific range, as measured by a gas adsorption method. .
  • Patent Documents 1 and 2 use gas adsorption methods to measure ultrafine pores ranging from 0.1 nm to several tens of nanometers, making it difficult to control during manufacturing and ensuring good results. It has not been easy to stably obtain an annealing separator that provides film properties.
  • magnesium oxide for annealing separator cannot completely prevent the occurrence of film defects in grain-oriented electrical steel sheets, and grain-oriented electrical steel sheets with excellent film properties cannot be stably obtained. Therefore, it lacked reliability. That is, magnesium oxide for use as an annealing separator with sufficient performance has not yet been found.
  • an object of the present invention is to provide magnesium oxide for use as an annealing separator for obtaining grain-oriented electrical steel sheets with excellent film properties. Specifically, it is an object of the present invention to provide magnesium oxide for an annealing separator that can form a forsterite film with excellent film appearance and film adhesion on the surface of a steel plate. Another object of the present invention is to propose a method for manufacturing a grain-oriented electrical steel sheet using the above-mentioned magnesium oxide for an annealing separator.
  • the present inventors decided to conduct research focusing on the macropore (approximately 100 nm or more) region of magnesium oxide particles for annealing separator, which has not received attention until now.
  • macropore approximately 100 nm or more region of magnesium oxide particles for annealing separator
  • mercury intrusion pore distribution measurement which is a method that can strictly evaluate pores
  • magnesium oxide with pore mode diameter and mode volume adjusted to a certain range we found that among magnesium oxides, magnesium oxide with pore mode diameter and mode volume adjusted to a certain range.
  • magnesium oxide is more suitable for obtaining grain-oriented electrical steel sheets with excellent coating appearance and coating adhesion, and the present invention has been achieved.
  • the gist of the present invention is that the BET specific surface area is 12.0 m 2 /g or more and 30.0 m 2 /g or less, and the mode diameter of the pores as measured by mercury intrusion pore distribution measurement is 0.1 ⁇ m or more and 0.1 ⁇ m or more.
  • the magnesium oxide for annealing separator has a pore size of less than 4 ⁇ m and a mode volume of pores of 1.3 cm 3 /g or more.
  • the magnesium oxide for annealing separator of the present invention has a CAA40% of 50 seconds or more and 170 seconds or less, a Cl content of 500 ppm or less, and a volume-based cumulative 50% particle diameter (D 50 ) of 0.5 ⁇ m or more. It is preferable that it is 7.0 ⁇ m or less.
  • the magnesium oxide for annealing separator of the present invention preferably has a total content of Zn, Zr, Ni, Co, and Mn of 200 ppm or more and 10,000 ppm or less, and preferably has a Zn content of 200 ppm or more and 10,000 ppm or less. More preferably, the Zn content is 200 ppm or more and 9000 ppm or less.
  • the gist of the present invention is an annealing separator containing the above-mentioned magnesium oxide for an annealing separator.
  • the annealing separator of the present invention grain-oriented electrical steel sheets with excellent magnetic properties and insulation properties can be manufactured.
  • the gist of the present invention is to form a SiO 2 film on the surface of a steel plate, and to form a forsterite film on the surface of the steel plate by applying the above-mentioned annealing separation agent to the surface of the SiO 2 film and annealing.
  • a method of manufacturing a grain-oriented electrical steel sheet comprising: By the manufacturing method of the present invention, a grain-oriented electrical steel sheet with excellent magnetic properties and insulation properties can be manufactured.
  • magnesium oxide for use as an annealing separator for obtaining grain-oriented electrical steel sheets with excellent magnetic properties and insulation properties.
  • the magnesium oxide for an annealing separator of the present invention has a BET specific surface area of 12.0 m 2 /g or more and 30.0 m 2 /g or less, and a pore mode diameter of 0.1 ⁇ m as measured by mercury intrusion pore distribution measurement.
  • the diameter is at least 0.4 ⁇ m, and the mode volume of the pores is at least 1.3 cm 3 /g.
  • the mode diameter and mode volume of the pores of magnesium oxide for an annealing separator are measured by mercury porosimetry.
  • the mercury intrusion method it is possible to measure the mode diameter and mode volume of pores in the macropore (approximately 100 nm or more) region of magnesium oxide particles, making it possible to strictly control these. It has become.
  • the mode diameter and mode volume of the pores of the magnesium oxide particles are measured as follows.
  • a cumulative pore volume curve showing the relationship between the pore diameter and cumulative pore volume of the magnesium oxide particles is obtained by measuring the pore distribution using mercury intrusion porosimetry.
  • the horizontal axis of the cumulative pore volume curve is the pore diameter determined from the mercury intrusion pressure, and the vertical axis is the cumulative pore volume.
  • the following formula (I) (Washburn's formula) is used to convert the mercury intrusion pressure to the pore diameter.
  • D -(1/P) ⁇ 4 ⁇ cos ⁇ (I)
  • D pore diameter (m)
  • P injection pressure of mercury (Pa)
  • surface tension of mercury (485 dyne cm -1 (0.485 Pa m))
  • the log differential pore volume distribution curve is the value (dV/d (logD)) obtained by dividing the difference (dV) in each measurement section of the pore volume by the difference value d (logD) treated as the logarithm of the pore diameter. This is calculated and plotted against the average pore diameter of each section.
  • the magnesium oxide for an annealing separator of the present invention has a pore mode diameter of 0.1 ⁇ m or more and less than 0.4 ⁇ m, preferably 0.15 ⁇ m or more and less than 0.3 ⁇ m, as measured by mercury intrusion pore distribution measurement. Further, the magnesium oxide for an annealing separator of the present invention has a pore mode volume of 1.3 cm 3 /g or more, preferably 1.4 cm 3 /g or more, as measured by mercury intrusion pore distribution measurement. The upper limit of the mode volume is, for example, less than 2.5 cm 3 /g, preferably less than 2.3 cm 3 /g, and more preferably less than 2.0 cm 3 /g.
  • Examples of the range of mode volume include 1.3 cm 3 /g or more and less than 2.5 cm 3 /g, preferably 1.3 cm 3 /g or more and less than 2.3 cm 3 /g, and 1.4 cm 3 /g or more and less than 2.3 cm 3 /g. More preferably, it is less than .0 cm 3 /g.
  • Magnesium oxide which has a pore mode diameter of 0.1 ⁇ m or more and less than 0.4 ⁇ m and a pore mode volume of 1.3 cm 3 /g or more as determined by mercury intrusion pore distribution measurement, is coated on the surface of the steel sheet. It is possible to form a forsterite film with excellent appearance and film adhesion.
  • magnesium oxide which has a pore mode diameter of 0.1 ⁇ m or more and less than 0.4 ⁇ m and a pore mode volume of less than 1.3 cm 3 /g as determined by mercury intrusion pore distribution measurement, is , it is not possible to form a forsterite film with excellent film appearance and film adhesion.
  • the pore diameter range of approximately 0.1 to 0.4 ⁇ m that is, the mode diameter range of the pores of the present invention determined by mercury intrusion pore distribution measurement is within the secondary particles where primary particles of magnesium oxide aggregate. It is thought that this corresponds to the diameter of the void.
  • a large value of mode volume is considered to indicate that the distribution of pore diameters is narrow and uniform.
  • magnesium oxide for an annealing separator, it is suspended in water together with additives, etc., and made into a slurry to form an annealing separator.
  • the magnesium oxide for the annealing separator of the present invention has a mode volume of pores of 1.3 cm 3 /g or more, and it is thought that the voids in the secondary particles are aligned in a narrow range. The degree of loosening of secondary particle aggregation and progress of hydration in water becomes uniform over time.
  • the magnesium oxide particles in the annealing separator can uniformly contribute to the film forming reaction, so it is presumed that a uniform film is formed.
  • the mode diameter of the pore is too small, the aggregation of secondary particles will be strong, and if the mode diameter of the pore is too large, the gaps between the primary particles will be too large, so the pore diameter should be 0.1 ⁇ m or more and 0.4 ⁇ m. Should be in the range less than or equal to
  • the mode diameter of the pores of magnesium oxide can be adjusted by known methods, such as controlling the firing temperature and time of magnesium hydroxide, crushing the magnesium oxide, and after crushing. Adjustments can also be made by measuring the mode diameter of the powder and pulverizing it multiple times, by pulverizing it using a pulverizer with a built-in classifier, and by measuring the mode diameter after pulverization and firing it multiple times.
  • the mode volume of the pores can be adjusted by various methods, such as adjusting the secondary particle size of the precursor magnesium hydroxide, adjusting the firing conditions of the precursor magnesium hydroxide, adding metal elements, and adjusting the magnesium oxide precursor.
  • There are several methods such as pulverization, pulverization multiple times by measuring the mode volume after pulverization, pulverization using a pulverizer with a built-in classifier, or adjusting the mode volume by mixing multiple magnesium oxide powders. , but not limited to.
  • adjustment can be made by adding Zn, Zr, Ni, Co, and Mn as metal elements in a predetermined range to magnesium oxide for an annealing separator and firing the mixture.
  • a certain amount of Zn, Zr , Ni, Co, and Mn can be adjusted to increase the mode volume.
  • the modal volume can be stably adjusted, and typically by adding a certain amount of Zn, the modal volume can be adjusted to increase.
  • the total content of Zn is preferably 200 ppm to 10,000 ppm. Preferably it is 250 ppm to 9500 ppm, more preferably 300 ppm to 9000 ppm. If the total content is less than 200 ppm or more than 10,000 ppm, magnesium oxide with a pore mode volume of 1.3 cm 3 /g or more cannot be obtained.
  • the contents of Zn, Zr, Ni, Co, and Mn can be controlled by a known method, for example, by a method for controlling the amount of trace amounts of content, which will be described later.
  • the above Zn, Zr, Ni, Co and Mn may be added to the magnesium oxide precursor for annealing separator in the form of their oxides, hydroxides, chlorides, sulfides, carbonates, sulfates, etc. I can do it.
  • Zn it is preferable to use zinc chloride and/or zinc oxide.
  • ppm in the specification means mass ppm unless otherwise specified.
  • the BET specific surface area of the magnesium oxide of the present invention is 12.0 m 2 /g or more and 30.0 m 2 /g or less.
  • the BET specific surface area of magnesium oxide is less than 12.0 m 2 /g, the primary particle size of magnesium oxide becomes coarse, the reactivity of the magnesium oxide particles deteriorates, the forsterite film formation rate decreases, and the oxidation Because magnesium particles are coarse, residues tend to remain when removed with acid.
  • the BET specific surface area of magnesium oxide is larger than 30.0 m 2 /g, the primary particle size of magnesium oxide becomes small and the reactivity of the magnesium oxide particles becomes too fast, making it difficult to form a uniform forsterite film. Therefore, in the present invention, the BET specific surface area is 12.0 m 2 /g or more and 30.0 m 2 /g or less, preferably 12.0 m 2 /g or more and 23.0 m 2 /g or less.
  • CAA uses a solid-liquid phase reaction to empirically simulate the reactivity of the solid-solid phase reaction between silicon dioxide and magnesium oxide that occurs on the surface of an actual electrical steel sheet. This is to measure the reactivity of magnesium particles. If the CAA40% of magnesium oxide is greater than 170 seconds, the reactivity of the magnesium oxide particles will be poor and the forsterite film formation rate will be slow, so a sufficient film will not be formed and the iron loss and magnetic flux density of the grain-oriented electrical steel sheet will decrease. characteristics tend to deteriorate.
  • CAA40% of magnesium oxide is less than 50 seconds, the reactivity of the magnesium oxide particles becomes too fast, making it impossible to form a uniform forsterite coating, resulting in poor coating appearance and coating adhesion on grain-oriented electrical steel sheets.
  • CAA40% is, for example, 50 seconds or more and 170 seconds or less, preferably in the range of 50 to 150 seconds, more preferably in the range of 60 to 130 seconds.
  • the volume-based cumulative 50% particle diameter (D 50 ) is preferably 0.5 ⁇ m or more and 7.0 ⁇ m or less.
  • the volume-based cumulative 50% particle diameter (D 50 ) is smaller than 0.5 ⁇ m, the activity is high and the aggregation becomes large, making it difficult to handle and forming a good film.
  • the volume-based cumulative 50% particle diameter (D 50 ) exceeds 7.0 ⁇ m, the primary particle diameter of magnesium oxide becomes coarse, the reactivity of the magnesium oxide particles worsens, and the rate of forsterite film formation slows down. , it becomes difficult to form a sufficient film.
  • D50 is 0.7 ⁇ m or more and 6.0 ⁇ m or less, and even more preferably 1.0 ⁇ m or more and 5.0 ⁇ m or less.
  • the magnesium oxide of the present invention can also contain, for example, calcium (Ca), silicon (Si), aluminum ( It can contain trace amounts of substances such as Al), iron (Fe), phosphorus (P), boron (B), sulfur (S), fluorine (F), and chlorine (Cl).
  • the magnesium oxide of the present invention contains calcium (Ca), the content of calcium is preferably 0.2 to 2.0% by mass in terms of CaO.
  • the magnesium oxide of the present invention contains silicon (Si), the silicon content is preferably 0.05 to 0.5% by mass.
  • the magnesium oxide of the present invention contains aluminum (Al), the content of aluminum is preferably 0.01 to 0.5% by mass.
  • the magnesium oxide of the present invention contains iron (Fe), the iron content is preferably 0.01 to 0.5% by mass.
  • the magnesium oxide of the present invention contains phosphorus (P), the content of phosphorus is preferably 0.01 to 0.15% by mass in terms of P 2 O 3 .
  • the magnesium oxide of the present invention contains boron (B), the boron content is preferably 0.04 to 0.15% by mass.
  • the sulfur content is preferably 0.01 to 1.5% by mass in terms of SO 3 .
  • the magnesium oxide of the present invention contains fluorine (F)
  • the content of fluorine is preferably 0.05% by mass or less.
  • the magnesium oxide of the present invention contains chlorine (Cl)
  • the content of chlorine is preferably 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less.
  • the magnesium oxide of the present invention may have a total pore area of 5 m 2 /g or more and less than 30 m 2 /g, for example, as determined by mercury intrusion pore distribution measurement;
  • the average pore diameter may be 0.2 ⁇ m or more and less than 3.0 ⁇ m.
  • the total pore area is the sum of pore areas calculated from measurement data assuming that the pores are cylindrical. For the total pore area and average pore diameter, values measured at an injection pressure of up to 59,950.54 psia are used.
  • the total pore area and average pore diameter of magnesium oxide can be adjusted by known methods, such as controlling the firing temperature and time of magnesium hydroxide, and further adjusting the total pore area and average pore diameter after pulverization. Adjustment can also be made by measuring and firing multiple times.
  • magnesium oxide In the present invention, a known method can be used for producing magnesium oxide. For example, using magnesium chloride as a raw material, calcium hydroxide is added in the form of a slurry to this aqueous solution and reacted to form magnesium hydroxide. Next, this magnesium hydroxide is filtered, washed with water, dried, and then fired in a heating furnace to form magnesium oxide, which can be pulverized to a desired particle size to produce it.
  • magnesium oxide is produced by the Aman process in which an aqueous solution containing magnesium chloride such as seawater, irrigation water, bittern, etc. is introduced into a reactor and magnesium oxide and hydrochloric acid are directly produced at 1773 to 2273 K. Magnesium oxide can be produced by grinding to a particle size of .
  • magnesium oxide can also be produced by hydrating magnesium oxide obtained by sintering the mineral magnesite, sintering the obtained magnesium hydroxide, and pulverizing it to a desired particle size.
  • the amount of trace content in MgO can be controlled by known methods.
  • As a method for controlling the amount of trace contents in MgO for example, during the manufacturing process of the crude product or by controlling the obtained crude product so that the amount of trace content in MgO is within a predetermined range. This can be done by controlling the amount of trace amounts of content before the final firing.
  • Control during the manufacturing process of crude products can be carried out, for example, by analyzing the amount of trace amounts contained in raw materials, and based on the results, using wet or dry methods to control the amount of trace contents to be controlled at a predetermined amount. It can be controlled by adding or removing by wet method. Addition of trace amounts of substances can be carried out, for example, by mixing the elements to be added and drying the mixture.
  • trace amounts of inclusions can be removed, for example, by physically cleaning the excess inclusions with a wet method or by chemically separating them.
  • Chemical separation can be accomplished, for example, by forming a soluble hydrate and separating it by dissolving, filtering, and washing, or by forming an insoluble compound and precipitating it, and separating it by adsorbing the precipitate. This can be done by
  • the amount of trace elements contained in the crude product before final calcination can be controlled by, for example, combining and mixing crude products with different compositions, so that the amount of trace elements is kept within a predetermined range. The shortage can be adjusted and controlled by final firing.
  • the above procedure is followed depending on the individual results regarding the amount of trace elements. can be repeated and combined.
  • the BET specific surface area, CAA40%, and D50 of magnesium oxide can be adjusted by a known method, for example, by the following method. That is, by adjusting the reaction temperature and the concentration of the alkali source during the manufacturing process of magnesium hydroxide, the primary particle size and secondary particle size of magnesium hydroxide can be controlled, and the BET specific surface area, CAA40%, and D 50 can be adjusted. Further, the BET specific surface area, CAA40%, and D50 of magnesium oxide can also be adjusted by controlling the firing temperature and time of magnesium hydroxide with a controlled particle size.
  • the BET specific surface area, CAA40%, and D50 can be measured after pulverization, and the results can be adjusted by performing firing multiple times.
  • the fired magnesium oxide can be processed into jaw crushers, gyratory crushers, cone crushers, impact crushers, roll crushers, cutter mills, stamp mills, ring mills, roller mills, jet mills, hammer mills, pin mills, rotary mills, vibrating mills,
  • the BET specific surface area, CAA40%, and D50 of magnesium oxide after pulverization can also be adjusted by pulverizing it using a pulverizer such as a planetary mill or a ball mill.
  • the BET specific surface area, CAA40%, and D50 can be measured after pulverization, and the pulverization is performed multiple times. Furthermore, the BET specific surface area, CAA40%, and D50 of magnesium oxide can also be adjusted using a pulverizer equipped with a classifier. Furthermore, the BET specific surface area, CAA40%, and D50 can also be adjusted by combining and mixing a plurality of magnesium oxide powders.
  • the grain-oriented electrical steel sheet of the present invention can be manufactured, for example, by the following method.
  • Grain-oriented electrical steel sheets are produced by hot rolling a silicon steel slab containing 2.5 to 4.5% Si, followed by pickling and cold rolling, or by cold rolling twice with intermediate annealing in between. Adjust to the specified thickness.
  • the cold-rolled coil is subjected to recrystallization annealing, which also serves as decarburization, in a wet hydrogen atmosphere at 923 to 1173 K, and at this time, an oxide film containing silica (SiO 2 ) as the main component is formed on the steel plate surface. .
  • An annealing separator containing magnesium oxide for an annealing separator of the present invention is uniformly dispersed in water to obtain a water slurry, and the water slurry is continuously applied onto the steel plate using roll coating or spraying, Dry at approximately 573K.
  • the thus treated steel plate coil is subjected to final finish annealing at, for example, 1473K for 20 hours to form a forsterite coating (Mg 2 SiO 4 ) on the steel plate surface.
  • the forsterite coating is an insulating coating and can impart tension to the surface of the steel sheet, thereby improving the iron loss value of the grain-oriented electrical steel sheet.
  • ⁇ Measurement method/test method> (1) Method for measuring the content of metal elements After completely dissolving the sample to be measured in acid, diluting it with ultrapure water, using an ICP emission spectrometer (PS3520 VDD, manufactured by Hitachi High-Tech Science Corporation), The content of metal elements was measured.
  • BET specific surface area was measured by gas adsorption method (BET method) using a specific surface area measuring device (trade name: Macsorb, manufactured by Mountech Co., Ltd.).
  • volume-based cumulative 50% particle diameter (D 50 ) Disperse the sample to be measured in methanol, and use a laser diffraction scattering particle size distribution analyzer (MT3300EX-II manufactured by LEEDS & NORTHRUP) to measure the sample size. The volume-based cumulative 50% particle diameter (D 50 ) was measured. At that time, the particles were dispersed for 180 seconds using ultrasonic waves with an output of 40 W.
  • D 50 volume-based cumulative 50% particle diameter
  • the particle size was adjusted using a standard sieve of 355 ⁇ 10 ⁇ 6 m). After this measurement cell was attached to the apparatus, the inside of the cell was maintained at a reduced pressure of 50 ⁇ Hg (6.67 Pa) or less for 20 minutes. Next, the measurement cell was filled with mercury until the pressure reached 1.5 psia (10342 Pa). Thereafter, mercury was injected at a pressure ranging from 2 psia (13,790 Pa) to 60,000 psia (413.7 MPa), and the pore distribution was measured. The mode diameter and mode volume were calculated from the obtained pore distribution.
  • the magnesium oxide of the present invention or the magnesium oxide of the comparative example was made into a slurry and applied to a steel plate so that the weight after drying was 14 g/ m2 , and after drying, it was heated at 1473K for 20.0 hours. Final annealing was performed. After finishing the final annealing, the steel plate was cooled, washed with water, acid-washed with an aqueous hydrochloric acid solution, washed with water again, and dried to form a forsterite film on the steel plate.
  • Example 1 Calcium hydroxide slurry was added to bittern containing magnesium ions at a concentration of 2.0 mol/L so that the magnesium hydroxide concentration after reaction was 1.2 mol/L to obtain a mixed solution. The mixture was stirred at 600 rpm and reacted at 323 K for 7.0 hours. Thereafter, it was filtered using a filter press, washed with water, and dried to obtain magnesium hydroxide. Zinc chloride (manufactured by Kanto Kagaku, reagent special grade) was mixed with this magnesium hydroxide so that the Zn content in the magnesium oxide after firing was 720 ppm, and the mixture was fired in a rotary kiln at 1173K for 0.5 hours, and then pulverized. Magnesium oxide powder of Example 1 was obtained. Note that the firing was performed under conditions such that the CAA of magnesium oxide was 40% in the range of 70 to 90 seconds.
  • Example 2 Magnesium oxide powder was obtained in the same manner as in Example 1, except that zinc chloride (special grade reagent) was mixed so that the Zn content in the magnesium oxide after firing was 2250 ppm.
  • Example 3 Magnesium oxide powder was obtained in the same manner as in Example 1, except that zinc chloride (special grade reagent) was mixed so that the Zn content in the magnesium oxide after firing was 4300 ppm.
  • Example 4 Calcium hydroxide slurry was added to bittern containing magnesium ions at a concentration of 2.0 mol/L so that the magnesium hydroxide concentration after reaction was 1.2 mol/L to obtain a mixed solution.
  • Zinc chloride manufactured by Kanto Kagaku, reagent special grade
  • Zinc chloride was mixed with this mixed solution so that the Zn content in the magnesium oxide after firing was 8800 ppm, and then the mixed solution was reacted at 323 K for 7.0 hours while stirring at 600 rpm. , and then filtered with a filter press, washed with water, and dried to obtain magnesium hydroxide.
  • This magnesium hydroxide was fired in a rotary kiln at 1173K for 0.5 hours and then pulverized to obtain magnesium oxide powder of Example 4. Note that the firing was performed under conditions such that the CAA of magnesium oxide was 40% in the range of 70 to 95 seconds.
  • Example 5 Magnesium oxide powder was prepared in the same manner as in Example 4, except that zinc oxide (manufactured by Wako Pure Chemical Industries, Ltd., reagent special grade) was mixed in place of zinc chloride so that the Zn content in the magnesium oxide after firing was 5250 ppm. Obtained.
  • magnesium oxide As is clear from Table 1, magnesium oxide ( It was revealed that the forsterite coatings formed using Examples 1 to 5) were excellent in (a) the appearance of the coating and (b) the adhesion of the coating. On the other hand, a forsterite coating formed using magnesium oxide (Comparative Example 1) with a pore mode volume of less than 1.3 cm 3 /g as measured by mercury intrusion pore distribution measurement has (a) appearance of the coating, ( b) Both the adhesion of the film was poor.
  • the magnesium oxide for annealing separator of the present invention can produce a grain-oriented electrical steel sheet having an excellent forsterite coating.
  • magnesium oxide for an annealing separator that can provide grain-oriented electrical steel sheets with excellent film properties.

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Abstract

The purpose of the present invention is to provide a magnesium oxide which is for an annealing separating agent and which is used for obtaining a grain-oriented electrical steel sheet having excellent coating characteristics. The present invention is a magnesium oxide for an annealing separating agent, for which the BET specific surface area is 12.0 m2/g to 30.0 m2/g and, according to measurement of the pore size distribution by mercury intrusion, the modal pore diameter is at least 0.1 µm but less than 0.4 µm and the modal pore volume is at least 1.3 cm3/g.

Description

焼鈍分離剤用酸化マグネシウム及び方向性電磁鋼板Magnesium oxide for annealing separator and grain-oriented electrical steel sheet
 本発明は、焼鈍分離剤用の酸化マグネシウム(MgO)及び方向性電磁鋼板に関する。 The present invention relates to magnesium oxide (MgO) for use as an annealing separator and grain-oriented electrical steel sheets.
 変圧器や発電機に使用される方向性電磁鋼板は、一般に、ケイ素(Si)を約3%含有する珪素鋼を、熱間圧延し、次いで最終板厚に冷間圧延し、次いで脱炭焼鈍、仕上げ焼鈍して、製造される。脱炭焼鈍(一次再結晶焼鈍)では、鋼板表面にSiO被膜を形成し、その表面に焼鈍分離剤用酸化マグネシウムを含むスラリーを塗布して乾燥させ、コイル状に巻取った後、仕上げ焼鈍することにより、SiOとMgOが反応してフォルステライト(MgSiO)被膜が鋼板表面に形成される。このフォルステライト被膜は、鋼板表面に張力を付加し、鉄損を低減して磁気特性を向上させ、また鋼板に絶縁性を付与する役割を果たす。 Grain-oriented electrical steel sheets used in transformers and generators are generally made of silicon steel containing about 3% silicon (Si), which is hot-rolled, then cold-rolled to the final thickness, and then decarburized and annealed. , finished annealing, and manufactured. In decarburization annealing (primary recrystallization annealing), a SiO 2 film is formed on the surface of the steel sheet, a slurry containing magnesium oxide for an annealing separation agent is applied to the surface, dried, wound into a coil shape, and then final annealed. By doing so, SiO 2 and MgO react to form a forsterite (Mg 2 SiO 4 ) film on the surface of the steel plate. This forsterite coating serves to add tension to the surface of the steel sheet, reduce iron loss, improve magnetic properties, and provide insulation to the steel sheet.
 このフォルステライト被膜が製品の外観や電気絶縁性の良否を決定し、さらには市場価値を左右する。被膜の生成過程は鋼板表層のインヒビター分解挙動、ひいては2次再結晶に影響する結果として、被膜の良否が製品の磁気特性の良否に影響を与える。さらに、被膜の外観は、方向性電磁鋼板の製品としての最終的な外観を左右する。そのため、被膜の外観は製品価値にも影響を与え、製品歩留まりに及ぼす影響も大きく、被膜が不均一な場合は製品の製造歩止りを低下させる。したがって、かかる被膜の特性を向上させることは方向性電磁鋼板の製造技術において重要な位置をしめている。 This forsterite film determines the product's appearance and electrical insulation, and also influences its market value. The film formation process affects the inhibitor decomposition behavior of the surface layer of the steel sheet, and ultimately the secondary recrystallization, and the quality of the film affects the quality of the magnetic properties of the product. Furthermore, the appearance of the coating influences the final appearance of the grain-oriented electrical steel sheet as a product. Therefore, the appearance of the coating has an impact on the product value and has a large effect on the product yield, and if the coating is non-uniform, the manufacturing yield of the product will be reduced. Therefore, improving the properties of such coatings plays an important role in the manufacturing technology of grain-oriented electrical steel sheets.
 従来、方向性電磁鋼板の特性を向上するために、焼鈍分離剤用酸化マグネシウムについての研究が行われ、品質改善のために、様々な工夫がなされており、例えば、B、CaO、SO、Clなどの不純物濃度、クエン酸活性度(CAA)、BET比表面積、粒度分布などの焼鈍分離剤用酸化マグネシウムの粉体特性について種々検討がなされてきた。しかしながら、方向性電磁鋼板の製造過程において酸化マグネシウムは非常に複雑な働きをすることから、酸化マグネシウムの各粉体特性の変化が方向性電磁鋼板の製品特性にどのような影響を及ぼしているかは、未だ完全には解明されていない。 Conventionally, in order to improve the properties of grain-oriented electrical steel sheets, research has been conducted on magnesium oxide as an annealing separator, and various efforts have been made to improve quality. For example, B, CaO, SO 3 , Various studies have been made on the powder characteristics of magnesium oxide for use as an annealing separator, such as the concentration of impurities such as Cl, citric acid activity (CAA), BET specific surface area, and particle size distribution. However, since magnesium oxide plays a very complex role in the manufacturing process of grain-oriented electrical steel sheets, it is unclear how changes in the powder properties of magnesium oxide affect the product properties of grain-oriented electrical steel sheets. , has not yet been completely elucidated.
 このようななか、酸化マグネシウム粒子の有する細孔に着目し、これを制御した焼鈍分離剤用酸化マグネシウムが提案されている。特許文献1には、酸化マグネシウム粒子のNガス吸着等温線や水蒸気吸着等温線の分布を特定の範囲とすることによって、方向性電磁鋼板の磁気特性と被膜特性を向上させる技術が開示されている。また、特許文献2には、ガス吸着法により測定した酸化マグネシウム粒子の細孔容積を特定の範囲に制御することによって、方向性電磁鋼板の磁気特性と被膜特性を向上させる技術が開示されている。 Under these circumstances, magnesium oxide for use as an annealing separator has been proposed, focusing on the pores of magnesium oxide particles and controlling the pores. Patent Document 1 discloses a technique for improving the magnetic properties and coating properties of a grain-oriented electrical steel sheet by setting the distribution of N2 gas adsorption isotherms and water vapor adsorption isotherms of magnesium oxide particles to a specific range. There is. Additionally, Patent Document 2 discloses a technique for improving the magnetic properties and coating properties of grain-oriented electrical steel sheets by controlling the pore volume of magnesium oxide particles within a specific range, as measured by a gas adsorption method. .
特開平10-088240号公報Japanese Patent Application Publication No. 10-088240 特開平10-046259号公報Japanese Patent Application Publication No. 10-046259
 しかしながら、特許文献1及び2の技術は、ガス吸着法により0.1nm~数十nmの極微細な細孔を測定対象とするものであるため、製造上での制御が困難であり、良好な被膜特性を与える焼鈍分離剤を安定的に得ることは容易ではなかった。 However, the techniques disclosed in Patent Documents 1 and 2 use gas adsorption methods to measure ultrafine pores ranging from 0.1 nm to several tens of nanometers, making it difficult to control during manufacturing and ensuring good results. It has not been easy to stably obtain an annealing separator that provides film properties.
 このため、前述した従来の焼鈍分離剤用酸化マグネシウムでは方向性電磁鋼板の被膜不良の発生を完全には防止できておらず、被膜特性に優れた方向性電磁鋼板を安定して得ることができないことから信頼性を欠いていた。すなわち、十分な性能を有する焼鈍分離剤用酸化マグネシウムは未だ見出されていない。 For this reason, the above-mentioned conventional magnesium oxide for annealing separator cannot completely prevent the occurrence of film defects in grain-oriented electrical steel sheets, and grain-oriented electrical steel sheets with excellent film properties cannot be stably obtained. Therefore, it lacked reliability. That is, magnesium oxide for use as an annealing separator with sufficient performance has not yet been found.
 そこで本発明は、被膜特性に優れた方向性電磁鋼板を得るための焼鈍分離剤用酸化マグネシウムを提供することを目的とする。具体的には、鋼板の表面に被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができる焼鈍分離剤用酸化マグネシウムを提供することを目的とする。また、本発明は、上記の焼鈍分離剤用酸化マグネシウムを用いた方向性電磁鋼板の製造方法を提案することを目的とする。 Therefore, an object of the present invention is to provide magnesium oxide for use as an annealing separator for obtaining grain-oriented electrical steel sheets with excellent film properties. Specifically, it is an object of the present invention to provide magnesium oxide for an annealing separator that can form a forsterite film with excellent film appearance and film adhesion on the surface of a steel plate. Another object of the present invention is to propose a method for manufacturing a grain-oriented electrical steel sheet using the above-mentioned magnesium oxide for an annealing separator.
 本発明者らは、上記課題を解決するために、これまで着目されてこなかった焼鈍分離剤用酸化マグネシウム粒子のマクロポア(概ね100nm以上)領域に着目して研究を行うこととし、とくにマクロな細孔を厳密に評価可能な方法である水銀圧入式細孔分布測定を用いて詳細な検討を行った結果、酸化マグネシウムの中でも、細孔のモード径及びモード容積を一定の範囲に調整した酸化マグネシウムが、被膜の外観、被膜の密着性に優れた方向性電磁鋼板を得るのにより適した酸化マグネシウムであることを見出し、本発明に至った。 In order to solve the above problems, the present inventors decided to conduct research focusing on the macropore (approximately 100 nm or more) region of magnesium oxide particles for annealing separator, which has not received attention until now. As a result of a detailed study using mercury intrusion pore distribution measurement, which is a method that can strictly evaluate pores, we found that among magnesium oxides, magnesium oxide with pore mode diameter and mode volume adjusted to a certain range. However, it has been discovered that magnesium oxide is more suitable for obtaining grain-oriented electrical steel sheets with excellent coating appearance and coating adhesion, and the present invention has been achieved.
 すなわち、本発明の要旨は、BET比表面積が12.0m/g以上30.0m/g以下であって、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g以上である、焼鈍分離剤用酸化マグネシウムにある。 That is, the gist of the present invention is that the BET specific surface area is 12.0 m 2 /g or more and 30.0 m 2 /g or less, and the mode diameter of the pores as measured by mercury intrusion pore distribution measurement is 0.1 μm or more and 0.1 μm or more. The magnesium oxide for annealing separator has a pore size of less than 4 μm and a mode volume of pores of 1.3 cm 3 /g or more.
 さらに、本発明の焼鈍分離剤用酸化マグネシウムは、CAA40%が50秒以上170秒以下であり、Clの含有量が500ppm以下、体積基準の累積50%粒子径(D50)が0.5μm以上7.0μm以下であることが好ましい。CAA40%、Cl含有量、D50が所定の範囲であることにより、鋼板の表面に被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができる焼鈍分離剤用酸化マグネシウムをより確実に得ることができる。 Furthermore, the magnesium oxide for annealing separator of the present invention has a CAA40% of 50 seconds or more and 170 seconds or less, a Cl content of 500 ppm or less, and a volume-based cumulative 50% particle diameter (D 50 ) of 0.5 μm or more. It is preferable that it is 7.0 μm or less. By setting CAA40%, Cl content, and D50 within the specified ranges, magnesium oxide for annealing separation agent can form a forsterite film with excellent film appearance and film adhesion on the surface of the steel sheet. You can definitely get it.
 さらに、本発明の焼鈍分離剤用酸化マグネシウムは、Zn、Zr、Ni、Co、Mnの合計含有量が200ppm以上10000ppm以下であることが好ましく、Znの含有量が200ppm以上10000ppm以下であることがより好ましく、Znの含有量が200ppm以上9000ppm以下であることがさらに好ましい。上記元素を所定の範囲で含有させることにより、酸化マグネシウムの細孔のモード容積を調整することができるため、より容易に細孔のモード容積と細孔のモード径とを所定の範囲に制御することが可能となる。このため、安定的に鋼板の表面に被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができる焼鈍分離剤用酸化マグネシウムを得ることができる。 Furthermore, the magnesium oxide for annealing separator of the present invention preferably has a total content of Zn, Zr, Ni, Co, and Mn of 200 ppm or more and 10,000 ppm or less, and preferably has a Zn content of 200 ppm or more and 10,000 ppm or less. More preferably, the Zn content is 200 ppm or more and 9000 ppm or less. By containing the above elements in a predetermined range, the mode volume of the pores of magnesium oxide can be adjusted, so the mode volume of the pores and the mode diameter of the pores can be more easily controlled within the predetermined range. becomes possible. Therefore, it is possible to obtain magnesium oxide for an annealing separator that can stably form a forsterite film with excellent film appearance and film adhesion on the surface of a steel plate.
 また、本発明の要旨は、上述の焼鈍分離剤用酸化マグネシウムを含む焼鈍分離剤にある。本発明の焼鈍分離剤を用いることにより、磁気特性及び絶縁特性に優れた方向性電磁鋼板を製造することができる。 Furthermore, the gist of the present invention is an annealing separator containing the above-mentioned magnesium oxide for an annealing separator. By using the annealing separator of the present invention, grain-oriented electrical steel sheets with excellent magnetic properties and insulation properties can be manufactured.
 また、本発明の要旨は、鋼板表面にSiO被膜を形成する工程と、上述の焼鈍分離剤をSiO被膜の表面に塗布し、焼鈍することにより、鋼板表面にフォルステライト被膜を形成する工程とを含む、方向性電磁鋼板の製造方法にある。本発明の製造方法により、磁気特性及び絶縁特性に優れた方向性電磁鋼板を製造することができる。 Further, the gist of the present invention is to form a SiO 2 film on the surface of a steel plate, and to form a forsterite film on the surface of the steel plate by applying the above-mentioned annealing separation agent to the surface of the SiO 2 film and annealing. A method of manufacturing a grain-oriented electrical steel sheet, comprising: By the manufacturing method of the present invention, a grain-oriented electrical steel sheet with excellent magnetic properties and insulation properties can be manufactured.
 本発明によれば、磁気特性及び絶縁特性に優れた方向性電磁鋼板を得るための焼鈍分離剤用酸化マグネシウムを提供することができる。具体的には、本発明によれば、鋼板の表面に、被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができる焼鈍分離剤用酸化マグネシウムを提供することができる。 According to the present invention, it is possible to provide magnesium oxide for use as an annealing separator for obtaining grain-oriented electrical steel sheets with excellent magnetic properties and insulation properties. Specifically, according to the present invention, it is possible to provide magnesium oxide for an annealing separator that can form a forsterite film with excellent film appearance and film adhesion on the surface of a steel plate.
 本発明の焼鈍分離剤用酸化マグネシウムは、BET比表面積が12.0m/g以上30.0m/g以下であって、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g以上である。 The magnesium oxide for an annealing separator of the present invention has a BET specific surface area of 12.0 m 2 /g or more and 30.0 m 2 /g or less, and a pore mode diameter of 0.1 μm as measured by mercury intrusion pore distribution measurement. The diameter is at least 0.4 μm, and the mode volume of the pores is at least 1.3 cm 3 /g.
 本発明において、焼鈍分離剤用酸化マグネシウムの細孔のモード径及びモード容積は、水銀圧入法により測定される。本発明では、水銀圧入法を用いることにより、酸化マグネシウム粒子のマクロポア(概ね100nm以上)領域にある細孔のモード径及びモード容積を測定することができており、これらの厳密な制御が可能となっている。 In the present invention, the mode diameter and mode volume of the pores of magnesium oxide for an annealing separator are measured by mercury porosimetry. In the present invention, by using the mercury intrusion method, it is possible to measure the mode diameter and mode volume of pores in the macropore (approximately 100 nm or more) region of magnesium oxide particles, making it possible to strictly control these. It has become.
 具体的には、以下のとおりにして、酸化マグネシウム粒子の細孔のモード径及びモード容積が測定される。まず、水銀圧入法による細孔分布測定により、酸化マグネシウム粒子の細孔直径と累積細孔容積との関係を示す累積細孔容積曲線を求める。累積細孔容積曲線の横軸は、水銀圧入圧力から求めた細孔直径であり、縦軸は、累積細孔容積である。水銀圧入圧力から細孔直径への換算は、下記(I)式(Washburnの式)を用いる。
D=-(1/P)・4γ・cosΨ    (I)
[ここで、D:細孔直径(m)、P:水銀の圧入圧力(Pa)、γ:水銀の表面張力(485dyne・cm-1(0.485Pa・m))、Ψ:水銀の接触角(130°=2.26893rad)である。]
 そして、求めた累積細孔容積曲線をlog微分細孔容積分布曲線に変換する。log微分細孔容積分布曲線とは、細孔容積の測定区間ごとの差分(dV)を、細孔直径の対数扱いの差分値d(logD)で割った値(dV/d(logD))を求め、これを各区間の平均細孔直径に対してプロットしたものである。このlog微分細孔容積分布曲線から(dV/d(logD))の最大値を細孔のモード容積として得、(dV/d(logD))の最大値に対応する細孔直径を細孔のモード径として得る。
Specifically, the mode diameter and mode volume of the pores of the magnesium oxide particles are measured as follows. First, a cumulative pore volume curve showing the relationship between the pore diameter and cumulative pore volume of the magnesium oxide particles is obtained by measuring the pore distribution using mercury intrusion porosimetry. The horizontal axis of the cumulative pore volume curve is the pore diameter determined from the mercury intrusion pressure, and the vertical axis is the cumulative pore volume. The following formula (I) (Washburn's formula) is used to convert the mercury intrusion pressure to the pore diameter.
D=-(1/P)・4γ・cosΨ (I)
[Here, D: pore diameter (m), P: injection pressure of mercury (Pa), γ: surface tension of mercury (485 dyne cm -1 (0.485 Pa m)), Ψ: contact angle of mercury (130°=2.26893 rad). ]
Then, the obtained cumulative pore volume curve is converted into a log differential pore volume distribution curve. The log differential pore volume distribution curve is the value (dV/d (logD)) obtained by dividing the difference (dV) in each measurement section of the pore volume by the difference value d (logD) treated as the logarithm of the pore diameter. This is calculated and plotted against the average pore diameter of each section. From this log differential pore volume distribution curve, the maximum value of (dV/d(logD)) is obtained as the mode volume of the pore, and the pore diameter corresponding to the maximum value of (dV/d(logD)) is determined as the pore mode volume. Obtained as the mode diameter.
 本発明の焼鈍分離剤用酸化マグネシウムは、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、好ましくは、0.15μm以上0.3μm未満である。また、本発明の焼鈍分離剤用酸化マグネシウムは、水銀圧入式細孔分布測定による細孔のモード容積が1.3cm/g以上であり、好ましくは、1.4cm/g以上である。モード容積の上限としては、例えば、2.5cm/g未満が例示でき、2.3cm/g未満が好ましく、2.0cm/g未満がより好ましい。モード容積の範囲としては、1.3cm/g以上2.5cm/g未満が例示でき、1.3cm/g以上2.3cm/g未満が好ましく、1.4cm/g以上2.0cm/g未満がより好ましい。 The magnesium oxide for an annealing separator of the present invention has a pore mode diameter of 0.1 μm or more and less than 0.4 μm, preferably 0.15 μm or more and less than 0.3 μm, as measured by mercury intrusion pore distribution measurement. Further, the magnesium oxide for an annealing separator of the present invention has a pore mode volume of 1.3 cm 3 /g or more, preferably 1.4 cm 3 /g or more, as measured by mercury intrusion pore distribution measurement. The upper limit of the mode volume is, for example, less than 2.5 cm 3 /g, preferably less than 2.3 cm 3 /g, and more preferably less than 2.0 cm 3 /g. Examples of the range of mode volume include 1.3 cm 3 /g or more and less than 2.5 cm 3 /g, preferably 1.3 cm 3 /g or more and less than 2.3 cm 3 /g, and 1.4 cm 3 /g or more and less than 2.3 cm 3 /g. More preferably, it is less than .0 cm 3 /g.
 水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g以上である酸化マグネシウムは、鋼板の表面に、被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができる。一方、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g未満である酸化マグネシウムは、鋼板の表面に、被膜の外観、被膜の密着性に優れたフォルステライト被膜を形成することができない。 Magnesium oxide, which has a pore mode diameter of 0.1 μm or more and less than 0.4 μm and a pore mode volume of 1.3 cm 3 /g or more as determined by mercury intrusion pore distribution measurement, is coated on the surface of the steel sheet. It is possible to form a forsterite film with excellent appearance and film adhesion. On the other hand, magnesium oxide, which has a pore mode diameter of 0.1 μm or more and less than 0.4 μm and a pore mode volume of less than 1.3 cm 3 /g as determined by mercury intrusion pore distribution measurement, is , it is not possible to form a forsterite film with excellent film appearance and film adhesion.
 このように、酸化マグネシウム粒子の細孔のモード径及びモード容積が酸化マグネシウムの性能に与えることの詳細なメカニズムは、まだ明確に解明されてはないが、本発明者らは次のように考えている。まず、水銀圧入式細孔分布測定による細孔直径約0.1~0.4μmの範囲(すなわち本発明の細孔のモード径の範囲)は、酸化マグネシウムの一次粒子が凝集した二次粒子内の空隙の径に相当すると考えられる。そして、モード容積の値が大きいことは、細孔直径の分布が狭く、揃っていることを示すと考えられる。ここで、焼鈍分離剤用酸化マグネシウムは、その使用時に添加剤等とともに水に懸濁し、スラリー化して焼鈍分離剤とし、これを鋼板に塗布、乾燥したのち、最終仕上焼鈍をおこなうのであるが、スラリー化時において、酸化マグネシウムは水中に一定の時間留まり、一部の水和が進行する。また、焼鈍中には、焼鈍分離剤は、水分やCOなどを放出し、塗布時より体積が減少する。このとき、本発明の焼鈍分離剤用酸化マグネシウムは、細孔のモード容積が1.3cm/g以上であり、二次粒子内の空隙が狭い範囲で揃っていると考えられるため、スラリー化時における水中での二次粒子凝集のほぐれや水和の進行の度合いが一様となる。このため、スラリー塗布時の均一性が保たれ、また、焼鈍中における水分やCOなどの放出による体積減少の影響のバラつきも低減される。その結果、焼鈍分離剤中の全ての酸化マグネシウム粒子が均質に被膜形成反応に寄与することできることから、均一な被膜が形成されるものと推測される。なお、細孔のモード径が小さすぎると二次粒子の凝集が強く、細孔のモード径が大きすぎると一次粒子間の隙間が大きすぎることから、細孔直径は0.1μm以上0.4μm未満の範囲にあるべきである。 Although the detailed mechanism of how the mode diameter and mode volume of the pores of magnesium oxide particles affect the performance of magnesium oxide has not yet been clearly elucidated, the present inventors believe that ing. First, the pore diameter range of approximately 0.1 to 0.4 μm (that is, the mode diameter range of the pores of the present invention) determined by mercury intrusion pore distribution measurement is within the secondary particles where primary particles of magnesium oxide aggregate. It is thought that this corresponds to the diameter of the void. A large value of mode volume is considered to indicate that the distribution of pore diameters is narrow and uniform. Here, when using magnesium oxide for an annealing separator, it is suspended in water together with additives, etc., and made into a slurry to form an annealing separator. This is applied to a steel plate, dried, and then final annealing is performed. During slurry formation, magnesium oxide remains in water for a certain period of time, and some hydration progresses. Further, during annealing, the annealing separator releases moisture, CO 2 , etc., and its volume decreases compared to when it was applied. At this time, the magnesium oxide for the annealing separator of the present invention has a mode volume of pores of 1.3 cm 3 /g or more, and it is thought that the voids in the secondary particles are aligned in a narrow range. The degree of loosening of secondary particle aggregation and progress of hydration in water becomes uniform over time. Therefore, uniformity during slurry application is maintained, and variations in the effect of volume reduction due to release of moisture, CO 2 , etc. during annealing are also reduced. As a result, all the magnesium oxide particles in the annealing separator can uniformly contribute to the film forming reaction, so it is presumed that a uniform film is formed. In addition, if the mode diameter of the pore is too small, the aggregation of secondary particles will be strong, and if the mode diameter of the pore is too large, the gaps between the primary particles will be too large, so the pore diameter should be 0.1 μm or more and 0.4 μm. Should be in the range less than or equal to
 本発明の焼鈍分離剤用酸化マグネシウムにおいて、酸化マグネシウムの細孔のモード径は、公知の方法により調整でき、例えば、水酸化マグネシウムの焼成温度及び時間を制御すること、酸化マグネシウムの粉砕、粉砕後のモード径を測定しての複数回粉砕、分級機を内蔵した粉砕機を用いた粉砕、さらに粉砕後のモード径を測定し、複数回焼成を行うことなどによっても調整することができる。 In the magnesium oxide for annealing separator of the present invention, the mode diameter of the pores of magnesium oxide can be adjusted by known methods, such as controlling the firing temperature and time of magnesium hydroxide, crushing the magnesium oxide, and after crushing. Adjustments can also be made by measuring the mode diameter of the powder and pulverizing it multiple times, by pulverizing it using a pulverizer with a built-in classifier, and by measuring the mode diameter after pulverization and firing it multiple times.
 細孔のモード容積は、種々の方法で調整することができ、例えば前駆体水酸化マグネシウムの二次粒子径の調整、前駆体水酸化マグネシウムの焼成条件の調整、金属元素の添加、酸化マグネシウムの粉砕、粉砕後のモード容積を測定しての複数回粉砕、分級機を内蔵した粉砕機を用いた粉砕、または複数の酸化マグネシウム粉末を混合することによりモード容積を調整するなどの方法があるが、これらに限定されない。例えば、焼鈍分離剤用酸化マグネシウムに金属元素としてZn、Zr、Ni、Co、Mnを所定の範囲で含有させ焼成することによって調整を行うことができ、典型的には、一定量のZn、Zr、Ni、Co、Mnを添加することによってモード容積を大きくするように調整できる。中でも、Znを好ましく用いることでモード容積の調整を安定的に行うことができ、典型的には一定量のZnを添加することによってモード容積の値を増加させるように調整できる。 The mode volume of the pores can be adjusted by various methods, such as adjusting the secondary particle size of the precursor magnesium hydroxide, adjusting the firing conditions of the precursor magnesium hydroxide, adding metal elements, and adjusting the magnesium oxide precursor. There are several methods such as pulverization, pulverization multiple times by measuring the mode volume after pulverization, pulverization using a pulverizer with a built-in classifier, or adjusting the mode volume by mixing multiple magnesium oxide powders. , but not limited to. For example, adjustment can be made by adding Zn, Zr, Ni, Co, and Mn as metal elements in a predetermined range to magnesium oxide for an annealing separator and firing the mixture. Typically, a certain amount of Zn, Zr , Ni, Co, and Mn can be adjusted to increase the mode volume. Among them, by preferably using Zn, the modal volume can be stably adjusted, and typically by adding a certain amount of Zn, the modal volume can be adjusted to increase.
 また、上記Znの合計含有量は、200ppm~10000ppmであることが望ましい。好ましくは、250ppm~9500ppmであり、より好ましくは300ppm~9000ppmである。合計含有量が200ppm未満または10000ppm超であると、細孔のモード容積が1.3cm/g以上となるような酸化マグネシウムが得られない。Zn、Zr、Ni、CoおよびMnの含有量は、公知の方法によって制御可能であり、例えば、後述する微量含有物の量を制御する方法によって制御できる。上記Zn、Zr、Ni、CoおよびMnは、これらの酸化物、水酸化物、塩化物、硫化物、炭酸塩、硫酸塩等の形態で、焼鈍分離剤用酸化マグネシウムの前駆体に添加することができる。とくにZnを添加する場合、塩化亜鉛及び/又は酸化亜鉛を使用することが好ましい。なお、明細書中ppmとは、特に断りのない限り、質量ppmを意味する。 Further, the total content of Zn is preferably 200 ppm to 10,000 ppm. Preferably it is 250 ppm to 9500 ppm, more preferably 300 ppm to 9000 ppm. If the total content is less than 200 ppm or more than 10,000 ppm, magnesium oxide with a pore mode volume of 1.3 cm 3 /g or more cannot be obtained. The contents of Zn, Zr, Ni, Co, and Mn can be controlled by a known method, for example, by a method for controlling the amount of trace amounts of content, which will be described later. The above Zn, Zr, Ni, Co and Mn may be added to the magnesium oxide precursor for annealing separator in the form of their oxides, hydroxides, chlorides, sulfides, carbonates, sulfates, etc. I can do it. In particular, when adding Zn, it is preferable to use zinc chloride and/or zinc oxide. Note that ppm in the specification means mass ppm unless otherwise specified.
 本発明の酸化マグネシウムのBET比表面積は12.0m/g以上30.0m/g以下である。酸化マグネシウムのBET比表面積が12.0m/g未満の場合、酸化マグネシウムの一次粒子径が粗大になり、酸化マグネシウム粒子の反応性が悪くなって、フォルステライト被膜生成率が低下し、また酸化マグネシウムの粒子が粗大なため、酸で除去した際の残留物が残りやすくなる。酸化マグネシウムのBET比表面積が30.0m/gより大きくなると、酸化マグネシウムの一次粒子径が小さくなり、酸化マグネシウム粒子の反応性が速くなりすぎて、均一なフォルステライト被膜ができにくくなる。よって、本発明においてBET比表面積は、12.0m/g以上30.0m/g以下であり、好ましくは12.0m/g以上23.0m/g以下である。 The BET specific surface area of the magnesium oxide of the present invention is 12.0 m 2 /g or more and 30.0 m 2 /g or less. When the BET specific surface area of magnesium oxide is less than 12.0 m 2 /g, the primary particle size of magnesium oxide becomes coarse, the reactivity of the magnesium oxide particles deteriorates, the forsterite film formation rate decreases, and the oxidation Because magnesium particles are coarse, residues tend to remain when removed with acid. When the BET specific surface area of magnesium oxide is larger than 30.0 m 2 /g, the primary particle size of magnesium oxide becomes small and the reactivity of the magnesium oxide particles becomes too fast, making it difficult to form a uniform forsterite film. Therefore, in the present invention, the BET specific surface area is 12.0 m 2 /g or more and 30.0 m 2 /g or less, preferably 12.0 m 2 /g or more and 23.0 m 2 /g or less.
 CAAは固相-液相反応により、実際の電磁鋼板の表面で起こる二酸化ケイ素と酸化マグネシウムとの固相-固相反応の反応性を、経験的にシミュレートしており、一次粒子を含む酸化マグネシウム粒子の反応性を測定するものである。酸化マグネシウムのCAA40%が170秒より大きければ、酸化マグネシウム粒子の反応性が悪く、フォルステライト被膜形成速度が遅くなることから、十分な被膜が形成されず、方向性電磁鋼板の鉄損及び磁束密度の特性が悪くなる傾向にある。他方、酸化マグネシウムのCAA40%が50秒未満であれば、酸化マグネシウム粒子の反応性が速くなりすぎ、均一なフォルステライト被膜ができなくなり、方向性電磁鋼板の被膜の外観、被膜の密着性が悪くなる傾向にある。すなわち、CAA40%は50秒未満では水和量が大きくなりすぎ、一方170秒を超えると反応性が低すぎて、良好な被膜特性が得られない傾向にある。よって、本発明においてCAA40%は、例えば、50秒以上170秒以下とし、好ましくは50~150秒の範囲、より好ましくは60~130秒の範囲とする。 CAA uses a solid-liquid phase reaction to empirically simulate the reactivity of the solid-solid phase reaction between silicon dioxide and magnesium oxide that occurs on the surface of an actual electrical steel sheet. This is to measure the reactivity of magnesium particles. If the CAA40% of magnesium oxide is greater than 170 seconds, the reactivity of the magnesium oxide particles will be poor and the forsterite film formation rate will be slow, so a sufficient film will not be formed and the iron loss and magnetic flux density of the grain-oriented electrical steel sheet will decrease. characteristics tend to deteriorate. On the other hand, if the CAA40% of magnesium oxide is less than 50 seconds, the reactivity of the magnesium oxide particles becomes too fast, making it impossible to form a uniform forsterite coating, resulting in poor coating appearance and coating adhesion on grain-oriented electrical steel sheets. There is a tendency to That is, when 40% CAA is used for less than 50 seconds, the amount of hydration becomes too large, while when it exceeds 170 seconds, the reactivity is too low and good film properties tend not to be obtained. Therefore, in the present invention, CAA40% is, for example, 50 seconds or more and 170 seconds or less, preferably in the range of 50 to 150 seconds, more preferably in the range of 60 to 130 seconds.
 体積基準の累積50%粒子径(D50)は0.5μm以上7.0μm以下が好ましい。体積基準の累積50%粒子径(D50)が0.5μmより小さいと、活性が高く、凝集も大きくなるため取扱いも難しく良好な被膜形成が困難となりやすい。体積基準の累積50%粒子径(D50)が7.0μmを超えると、酸化マグネシウムの一次粒子径が粗大になり、酸化マグネシウム粒子の反応性が悪くなるため、フォルステライト被膜形成速度が遅くなり、十分な被膜が形成されにくくなる。より好ましいD50は0.7μm以上6.0μm以下であり、さらに好ましくは1.0μm以上5.0μm以下である。 The volume-based cumulative 50% particle diameter (D 50 ) is preferably 0.5 μm or more and 7.0 μm or less. When the volume-based cumulative 50% particle diameter (D 50 ) is smaller than 0.5 μm, the activity is high and the aggregation becomes large, making it difficult to handle and forming a good film. When the volume-based cumulative 50% particle diameter (D 50 ) exceeds 7.0 μm, the primary particle diameter of magnesium oxide becomes coarse, the reactivity of the magnesium oxide particles worsens, and the rate of forsterite film formation slows down. , it becomes difficult to form a sufficient film. More preferably, D50 is 0.7 μm or more and 6.0 μm or less, and even more preferably 1.0 μm or more and 5.0 μm or less.
 本発明の酸化マグネシウムは、前述の亜鉛(Zn)、ジルコニウム(Zr)、ニッケル(Ni)、コバルト(Co)、マンガン(Mn)の他、例えば、カルシウム(Ca)、珪素(Si)、アルミニウム(Al)、鉄(Fe)、リン(P)、ホウ素(B)、硫黄(S)、フッ素(F)、及び塩素(Cl)等の微量含有物を含むことができる。 In addition to the aforementioned zinc (Zn), zirconium (Zr), nickel (Ni), cobalt (Co), and manganese (Mn), the magnesium oxide of the present invention can also contain, for example, calcium (Ca), silicon (Si), aluminum ( It can contain trace amounts of substances such as Al), iron (Fe), phosphorus (P), boron (B), sulfur (S), fluorine (F), and chlorine (Cl).
 本発明の酸化マグネシウムがカルシウム(Ca)を含む場合、カルシウムの含有量は、CaO換算で0.2~2.0質量%であることが好ましい。本発明の酸化マグネシウムが珪素(Si)を含む場合、珪素の含有量は、0.05~0.5質量%であることが好ましい。本発明の酸化マグネシウムがアルミニウム(Al)を含む場合、アルミニウムの含有量は、0.01~0.5質量%であることが好ましい。本発明の酸化マグネシウムが鉄(Fe)を含む場合、鉄の含有量は、0.01~0.5質量%であることが好ましい。本発明の酸化マグネシウムがリン(P)を含む場合、リンの含有量は、P換算で0.01~0.15質量%であることが好ましい。本発明の酸化マグネシウムがホウ素(B)を含む場合、ホウ素の含有量は、0.04~0.15質量%であることが好ましい。本発明の酸化マグネシウムが硫黄(S)を含む場合、硫黄の含有量は、SO換算で0.01~1.5質量%であることが好ましい。本発明の酸化マグネシウムがフッ素(F)を含む場合、フッ素の含有量は、0.05質量%以下であることが好ましい。本発明の酸化マグネシウムが塩素(Cl)を含む場合、塩素の含有量は、500ppm以下であることが好ましく、400ppm以下がより好ましく、300ppm以下がさらに好ましい。 When the magnesium oxide of the present invention contains calcium (Ca), the content of calcium is preferably 0.2 to 2.0% by mass in terms of CaO. When the magnesium oxide of the present invention contains silicon (Si), the silicon content is preferably 0.05 to 0.5% by mass. When the magnesium oxide of the present invention contains aluminum (Al), the content of aluminum is preferably 0.01 to 0.5% by mass. When the magnesium oxide of the present invention contains iron (Fe), the iron content is preferably 0.01 to 0.5% by mass. When the magnesium oxide of the present invention contains phosphorus (P), the content of phosphorus is preferably 0.01 to 0.15% by mass in terms of P 2 O 3 . When the magnesium oxide of the present invention contains boron (B), the boron content is preferably 0.04 to 0.15% by mass. When the magnesium oxide of the present invention contains sulfur (S), the sulfur content is preferably 0.01 to 1.5% by mass in terms of SO 3 . When the magnesium oxide of the present invention contains fluorine (F), the content of fluorine is preferably 0.05% by mass or less. When the magnesium oxide of the present invention contains chlorine (Cl), the content of chlorine is preferably 500 ppm or less, more preferably 400 ppm or less, and even more preferably 300 ppm or less.
 本発明の酸化マグネシウムは、例えば、水銀圧入式細孔分布測定による総細孔面積が5m/g以上30m/g未満であってもよく、また、例えば、水銀圧入式細孔分布測定による平均細孔径が0.2μm以上3.0μm未満であってもよい。なお、本発明において、総細孔面積は細孔を円筒形と仮定して測定データから求めた細孔面積の総和である。総細孔面積及び平均細孔径は、圧入圧力が59,950.54psiaまでの測定値を用いる。また、酸化マグネシウムの総細孔面積及び平均細孔径は、公知の方法により調整でき、例えば、水酸化マグネシウムの焼成温度及び時間を制御すること、さらに粉砕後の総細孔面積及び平均細孔径を測定し、複数回焼成を行うことなどによっても調整することができる。 The magnesium oxide of the present invention may have a total pore area of 5 m 2 /g or more and less than 30 m 2 /g, for example, as determined by mercury intrusion pore distribution measurement; The average pore diameter may be 0.2 μm or more and less than 3.0 μm. In the present invention, the total pore area is the sum of pore areas calculated from measurement data assuming that the pores are cylindrical. For the total pore area and average pore diameter, values measured at an injection pressure of up to 59,950.54 psia are used. In addition, the total pore area and average pore diameter of magnesium oxide can be adjusted by known methods, such as controlling the firing temperature and time of magnesium hydroxide, and further adjusting the total pore area and average pore diameter after pulverization. Adjustment can also be made by measuring and firing multiple times.
 本発明において、酸化マグネシウムの製造方法は公知の方法を用いることができる。例えば、原料として塩化マグネシウムを用い、この水溶液に水酸化カルシウムをスラリーの状態で添加し反応させ、水酸化マグネシウムを形成する。次いで、この水酸化マグネシウムを、ろ過、水洗、乾燥させた後、加熱炉で焼成し、酸化マグネシウムを形成し、これを所望の粒径まで粉砕して、製造することができる。 In the present invention, a known method can be used for producing magnesium oxide. For example, using magnesium chloride as a raw material, calcium hydroxide is added in the form of a slurry to this aqueous solution and reacted to form magnesium hydroxide. Next, this magnesium hydroxide is filtered, washed with water, dried, and then fired in a heating furnace to form magnesium oxide, which can be pulverized to a desired particle size to produce it.
 また、水酸化カルシウムの代わりに、水酸化ナトリウム、水酸化カリウム等の水酸基を有するアルカリ性化合物を用いることもできる。また、海水、潅水、苦汁等のような塩化マグネシウム含有水溶液を反応器に導入し、1773~2273Kで直接酸化マグネシウムと塩酸を生成させるアマン法(Aman process)により酸化マグネシウムを生成させ、これを所望の粒径まで粉砕して、酸化マグネシウムを製造することができる。 Furthermore, instead of calcium hydroxide, an alkaline compound having a hydroxyl group such as sodium hydroxide or potassium hydroxide can also be used. In addition, magnesium oxide is produced by the Aman process in which an aqueous solution containing magnesium chloride such as seawater, irrigation water, bittern, etc. is introduced into a reactor and magnesium oxide and hydrochloric acid are directly produced at 1773 to 2273 K. Magnesium oxide can be produced by grinding to a particle size of .
 更に、鉱物マグネサイトを焼成して得た酸化マグネシウムを、水和させ、得られた水酸化マグネシウムを焼成し、これを所望の粒径まで粉砕して、酸化マグネシウムを製造することもできる。 Further, magnesium oxide can also be produced by hydrating magnesium oxide obtained by sintering the mineral magnesite, sintering the obtained magnesium hydroxide, and pulverizing it to a desired particle size.
 MgO中の微量含有物の量は、公知の方法により制御できる。MgO中の微量含有物の量を制御する方法としては、例えば、MgO中の微量含有物の量が所定の範囲となるように、粗生成物の製造工程中に、又は得られた粗生成物の微量含有物量を最終焼成前に制御することにより行うことができる。粗生成物の製造工程中での制御は、例えば、原料に含まれる微量含有物の量を分析し、その結果を踏まえ、制御する対象の微量含有物が所定量となるように、湿式又は乾式で添加するか、湿式で除去することにより制御することができる。微量含有物の添加は、例えば、添加する元素を混合し、乾燥させることにより行うことができる。また、微量含有物の除去は、例えば、湿式で過剰な含有物を物理的に洗浄するか、化学的に分離することにより行うことができる。化学的な分離は、例えば、可溶性の水和物を形成させて、溶解させ、ろ過し、洗浄して分離するか、又は不溶性の化合物を形成させて、析出させ、析出物を吸着して分離することにより行うことができる。最終焼成前での粗生成物の微量含有物量の制御は、例えば、異なる組成を有する粗生成物を組み合わせて混合することで、微量含有物が所定の範囲となるように微量元素の量の過不足を調整し、これを最終焼成することにより制御できる。更に、微量含有元素の量を制御するため、いずれの場合も、粗生成物MgOを製造し、得られたMgOを分析した後、微量含有元素の量に関する個々の結果に応じて、上記の手順を繰り返し、組み合わせることができる。 The amount of trace content in MgO can be controlled by known methods. As a method for controlling the amount of trace contents in MgO, for example, during the manufacturing process of the crude product or by controlling the obtained crude product so that the amount of trace content in MgO is within a predetermined range. This can be done by controlling the amount of trace amounts of content before the final firing. Control during the manufacturing process of crude products can be carried out, for example, by analyzing the amount of trace amounts contained in raw materials, and based on the results, using wet or dry methods to control the amount of trace contents to be controlled at a predetermined amount. It can be controlled by adding or removing by wet method. Addition of trace amounts of substances can be carried out, for example, by mixing the elements to be added and drying the mixture. In addition, trace amounts of inclusions can be removed, for example, by physically cleaning the excess inclusions with a wet method or by chemically separating them. Chemical separation can be accomplished, for example, by forming a soluble hydrate and separating it by dissolving, filtering, and washing, or by forming an insoluble compound and precipitating it, and separating it by adsorbing the precipitate. This can be done by The amount of trace elements contained in the crude product before final calcination can be controlled by, for example, combining and mixing crude products with different compositions, so that the amount of trace elements is kept within a predetermined range. The shortage can be adjusted and controlled by final firing. Furthermore, in order to control the amount of trace elements, in each case after producing the crude product MgO and analyzing the MgO obtained, the above procedure is followed depending on the individual results regarding the amount of trace elements. can be repeated and combined.
 酸化マグネシウムのBET比表面積、CAA40%及びD50は、公知の方法により調整でき、例えば、次のような方法により行うことができる。すなわち、水酸化マグネシウムの製造工程中の反応温度及びアルカリ源の濃度を調整することにより、水酸化マグネシウムの一次粒子径及び二次粒子径を制御し、酸化マグネシウムのBET比表面積、CAA40%及びD50を調整することができる。また、粒子径を制御した水酸化マグネシウムの焼成温度及び時間を制御することによっても、酸化マグネシウムのBET比表面積、CAA40%及びD50を調整することができる。また、BET比表面積、CAA40%及びD50の調整方法として、粉砕後のBET比表面積、CAA40%及びD50を測定し、複数回焼成を行うことでも調整することができる。更に、焼成した酸化マグネシウムを、ジョークラッシャー、ジャイレトリークラッシャー、コーンクラッシャー、インパクトクラッシャー、ロールクラッシャー、カッターミル、スタンプミル、リングミル、ローラーミル、ジェットミル、ハンマーミル、ピンミル、回転ミル、振動ミル、遊星ミル、ボールミル等の粉砕機を使用して粉砕することによっても、酸化マグネシウムの粉砕後のBET比表面積、CAA40%及びD50を調整することができる。また、BET比表面積、CAA40%及びD50の調整方法として、粉砕後のBET比表面積、CAA40%及びD50を測定し、複数回粉砕を行うことでも調整することができる。また、分級機を内蔵した粉砕機を用いても酸化マグネシウムのBET比表面積、CAA40%及びD50を調整することができる。また、複数の酸化マグネシウム粉末を組み合わせて、それらを混合することによっても、BET比表面積、CAA40%及びD50の調整することができる。 The BET specific surface area, CAA40%, and D50 of magnesium oxide can be adjusted by a known method, for example, by the following method. That is, by adjusting the reaction temperature and the concentration of the alkali source during the manufacturing process of magnesium hydroxide, the primary particle size and secondary particle size of magnesium hydroxide can be controlled, and the BET specific surface area, CAA40%, and D 50 can be adjusted. Further, the BET specific surface area, CAA40%, and D50 of magnesium oxide can also be adjusted by controlling the firing temperature and time of magnesium hydroxide with a controlled particle size. Further, as a method for adjusting the BET specific surface area, CAA40%, and D50 , the BET specific surface area, CAA40%, and D50 can be measured after pulverization, and the results can be adjusted by performing firing multiple times. Furthermore, the fired magnesium oxide can be processed into jaw crushers, gyratory crushers, cone crushers, impact crushers, roll crushers, cutter mills, stamp mills, ring mills, roller mills, jet mills, hammer mills, pin mills, rotary mills, vibrating mills, The BET specific surface area, CAA40%, and D50 of magnesium oxide after pulverization can also be adjusted by pulverizing it using a pulverizer such as a planetary mill or a ball mill. Further, as a method for adjusting the BET specific surface area, CAA40%, and D50 , the BET specific surface area, CAA40%, and D50 can be measured after pulverization, and the pulverization is performed multiple times. Furthermore, the BET specific surface area, CAA40%, and D50 of magnesium oxide can also be adjusted using a pulverizer equipped with a classifier. Furthermore, the BET specific surface area, CAA40%, and D50 can also be adjusted by combining and mixing a plurality of magnesium oxide powders.
 本発明の方向性電磁鋼板は、例えば、下記のような方法で製造することができる。方向性電磁鋼板はSi 2.5~4.5%を含有するケイ素鋼スラブを熱間圧延し、酸洗後、冷間圧延を行うか、中間焼鈍をはさむ2回冷間圧延を行って、所定の板厚に調整する。次に、冷間圧延したコイルを923~1173Kの湿潤水素雰囲気中で、脱炭を兼ねた再結晶焼鈍を行い、このとき鋼板表面にシリカ(SiO)を主成分とする酸化被膜を形成させる。本発明の焼鈍分離剤用酸化マグネシウムを含む焼鈍分離剤を水に均一に分散させ、水スラリーを得て、この鋼板上に、水スラリーを、ロールコーティング又はスプレーを用いて連続的に塗布し、約573Kで乾燥させる。こうして処理された鋼板コイルを、例えば、1473Kで20時間の最終仕上げ焼鈍を行って、鋼板表面にフォルステライト被膜(MgSiO)を形成する。フォルステライト被膜は、絶縁被膜であるとともに、鋼板表面に張力を付与して、方向性電磁鋼板の鉄損値を向上させることができる。 The grain-oriented electrical steel sheet of the present invention can be manufactured, for example, by the following method. Grain-oriented electrical steel sheets are produced by hot rolling a silicon steel slab containing 2.5 to 4.5% Si, followed by pickling and cold rolling, or by cold rolling twice with intermediate annealing in between. Adjust to the specified thickness. Next, the cold-rolled coil is subjected to recrystallization annealing, which also serves as decarburization, in a wet hydrogen atmosphere at 923 to 1173 K, and at this time, an oxide film containing silica (SiO 2 ) as the main component is formed on the steel plate surface. . An annealing separator containing magnesium oxide for an annealing separator of the present invention is uniformly dispersed in water to obtain a water slurry, and the water slurry is continuously applied onto the steel plate using roll coating or spraying, Dry at approximately 573K. The thus treated steel plate coil is subjected to final finish annealing at, for example, 1473K for 20 hours to form a forsterite coating (Mg 2 SiO 4 ) on the steel plate surface. The forsterite coating is an insulating coating and can impart tension to the surface of the steel sheet, thereby improving the iron loss value of the grain-oriented electrical steel sheet.
 下記の実施例により本発明を詳細に説明するが、これらの実施例は本発明をいかなる意味においても制限するものではない。 The present invention will be explained in detail with reference to the following examples, but these examples are not intended to limit the present invention in any way.
<測定方法・試験方法>
(1)金属元素の含有量の測定方法
 測定試料を完全に酸溶解させた後、超純水で希釈し、ICP発光分光分析装置(PS3520 VDD 株式会社日立ハイテクサイエンス製)を用いて、試料中の金属元素の含有量を測定した。
<Measurement method/test method>
(1) Method for measuring the content of metal elements After completely dissolving the sample to be measured in acid, diluting it with ultrapure water, using an ICP emission spectrometer (PS3520 VDD, manufactured by Hitachi High-Tech Science Corporation), The content of metal elements was measured.
(2)塩素(Cl)の含有量の測定方法
 測定試料を硝酸に溶解した後、超純水で希釈し、分光光度計(UV-2550 島津製作所製)を用いて質量を測定することで、試料中の塩素(Cl)濃度を算出した。
(2) Method for measuring the content of chlorine (Cl) After dissolving the measurement sample in nitric acid, diluting it with ultrapure water and measuring the mass using a spectrophotometer (UV-2550 manufactured by Shimadzu Corporation), The chlorine (Cl) concentration in the sample was calculated.
(3)BET比表面積の測定方法
 比表面積測定装置(商品名:Macsorb、Mountech Co., Ltd.製)を使用して、ガス吸着法(BET法)によりBET比表面積を測定した。
(3) Method for measuring BET specific surface area BET specific surface area was measured by gas adsorption method (BET method) using a specific surface area measuring device (trade name: Macsorb, manufactured by Mountech Co., Ltd.).
(4)体積基準の累積50%粒子径(D50)の測定方法
 測定試料をメタノールに分散し、レーザー回折散乱式粒子径分布測定装置(MT3300EX-II LEEDS & NORTHRUP製)を用いて、試料の体積基準の累積50%粒子径(D50)を測定した。その際、出力40Wの超音波で180秒間分散した。
(4) Method for measuring volume-based cumulative 50% particle diameter (D 50 ) Disperse the sample to be measured in methanol, and use a laser diffraction scattering particle size distribution analyzer (MT3300EX-II manufactured by LEEDS & NORTHRUP) to measure the sample size. The volume-based cumulative 50% particle diameter (D 50 ) was measured. At that time, the particles were dispersed for 180 seconds using ultrasonic waves with an output of 40 W.
(5)CAA40%の測定方法
 0.4Nのクエン酸溶液100mLと、指示薬として適量(2mL)の1%フェノールフタレイン液とを、200mLビーカーに入れ、液温を303Kに調整し、マグネチックスターラーを使用して700rpmで攪拌しながら、クエン酸溶液中に40%の最終反応当量の酸化マグネシウム(2.0g)を投入して、最終反応までの時間、つまりクエン酸が消費され溶液が中性となるまでの時間を測定した。
(5) Method for measuring 40% CAA Put 100 mL of 0.4N citric acid solution and an appropriate amount (2 mL) of 1% phenolphthalein solution as an indicator into a 200 mL beaker, adjust the liquid temperature to 303 K, and use a magnetic stirrer. 40% final reaction equivalent of magnesium oxide (2.0 g) was added to the citric acid solution while stirring at 700 rpm using a The time required for this to occur was measured.
(6)モード径及びモード容積の測定方法
 水銀圧入式細孔分布測定装置として、「オートポアIV9510(商品名)」(マイクロメリティックス社製)を使用した。水銀は、純度99.5mass%以上、密度13.5335×10kg/mである特級の水銀試薬を用いた。測定セルは、セル内容積5×10-6、ステム容積0.39×10-6の粉体試料用セルを用いた。測定試料である各酸化マグネシウム粉末を、質量0.10×10-3~0.13×10-3kgの範囲で精密に秤量し、測定セルに充填した(なお、測定試料は、あらかじめ目開き355×10-6mの標準篩で粒径を揃えた)。この測定セルを装置に装着した後、セル内部を圧力50μHg(6.67Pa)以下で20分間、減圧状態に保持した。次に、測定セル内に、圧力が1.5psia(10342Pa)になるまで水銀を充填した。その後、圧力2psia(13790Pa)から60000psia(413.7MPa)の範囲で水銀を圧入して、細孔分布を測定した。得られた細孔分布より、モード径及びモード容積を算出した。
(6) Method for measuring mode diameter and mode volume “Autopore IV9510 (trade name)” (manufactured by Micromeritics) was used as a mercury intrusion type pore distribution measuring device. As the mercury, a special grade mercury reagent having a purity of 99.5 mass% or more and a density of 13.5335×10 3 kg/m 3 was used. The measurement cell used was a powder sample cell with an internal cell volume of 5×10 −6 m 3 and a stem volume of 0.39×10 −6 m 3 . Each magnesium oxide powder serving as a measurement sample was accurately weighed within a mass range of 0.10×10 −3 to 0.13×10 −3 kg, and filled into a measurement cell (the measurement sample should be pre-opened). The particle size was adjusted using a standard sieve of 355×10 −6 m). After this measurement cell was attached to the apparatus, the inside of the cell was maintained at a reduced pressure of 50 μHg (6.67 Pa) or less for 20 minutes. Next, the measurement cell was filled with mercury until the pressure reached 1.5 psia (10342 Pa). Thereafter, mercury was injected at a pressure ranging from 2 psia (13,790 Pa) to 60,000 psia (413.7 MPa), and the pore distribution was measured. The mode diameter and mode volume were calculated from the obtained pore distribution.
 なお、水銀の圧入圧力を細孔直径に換算するには、下記(I)式(Washburnの式)を用いて変換する。
    D=-(1/P)・4γ・cosΨ    (I)
ここで、
    D:細孔直径(m)、
    P:水銀の圧入圧力(Pa)、
    γ:水銀の表面張力(485dyne・cm-1(0.485Pa・m))、
    Ψ:水銀の接触角(130°=2.26893rad)である。
In addition, in order to convert the injection pressure of mercury into a pore diameter, the following formula (I) (Washburn's formula) is used.
D=-(1/P)・4γ・cosΨ (I)
here,
D: pore diameter (m),
P: Injection pressure of mercury (Pa),
γ: Surface tension of mercury (485 dyne cm -1 (0.485 Pa m)),
Ψ: Contact angle of mercury (130°=2.26893 rad).
(7)試験用鋼板の作成
 試験試料供試鋼として、方向性電磁鋼板用の珪素鋼スラブを、公知の方法で熱間圧延、冷間圧延を行って、最終板厚0.28mmとし、更に、窒素25%+水素75%の湿潤雰囲気中で脱炭焼鈍した鋼板を用いた。脱炭焼鈍前の鋼板の組成は、質量%で、C:0.01%、Si:3.29%、Mn:0.09%、Al:0.03%、S:0.07%、N:0.0053%、残部は不可避的な不純物とFeである。この鋼板上に酸化マグネシウムを塗布して、フォルステライト被膜を形成させ、その被膜特性を調査した。
(7) Preparation of steel plate for test As a test sample steel, a silicon steel slab for grain-oriented electrical steel plate was hot-rolled and cold-rolled to a final plate thickness of 0.28 mm by a known method, and then A steel plate decarburized and annealed in a humid atmosphere of 25% nitrogen and 75% hydrogen was used. The composition of the steel plate before decarburization annealing is, in mass%, C: 0.01%, Si: 3.29%, Mn: 0.09%, Al: 0.03%, S: 0.07%, N. :0.0053%, the remainder being unavoidable impurities and Fe. Magnesium oxide was applied onto this steel plate to form a forsterite film, and the properties of the film were investigated.
 具体的には、本発明の酸化マグネシウム又は比較例の酸化マグネシウムをスラリー状にして、乾燥後の重量で14g/mになるように鋼板に塗布し、乾燥後、1473Kで20.0時間の最終仕上げ焼鈍を行った。最終仕上げ焼鈍が終了したのち冷却し、鋼板を水洗し、塩酸水溶液で酸洗浄した後、再度水洗して、乾燥させ、鋼板上にフォルステライト被膜を形成させた。 Specifically, the magnesium oxide of the present invention or the magnesium oxide of the comparative example was made into a slurry and applied to a steel plate so that the weight after drying was 14 g/ m2 , and after drying, it was heated at 1473K for 20.0 hours. Final annealing was performed. After finishing the final annealing, the steel plate was cooled, washed with water, acid-washed with an aqueous hydrochloric acid solution, washed with water again, and dried to form a forsterite film on the steel plate.
(8)フォルステライト被膜外観の評価
 フォルステライト被膜の外観は、洗浄後の被膜の外観から判断した。すなわち、灰色のフォルステライト被膜が、均一に厚く形成されている場合を◎、被膜が均一であるがやや薄く形成されている場合を○、被膜が不均一で薄いが、下地の鋼板が露出している部分がない場合、もしくは被膜が不均一で非常に薄く、下地の鋼板が明らかに露出した部分がある場合を×とした。
(8) Evaluation of the appearance of the forsterite film The appearance of the forsterite film was judged from the appearance of the film after cleaning. In other words, ◎ indicates that the gray forsterite coating is uniformly thick, ○ indicates that the coating is uniform but slightly thin, and ○ indicates that the coating is uneven and thin, but the underlying steel plate is exposed. If there is no part where the coating is coated, or if the coating is uneven and very thin, and there is a part where the underlying steel plate is clearly exposed, it is rated as ×.
(9)フォルステライト被膜の密着性の評価
 フォルステライト被膜の密着性は、被膜状態から判断した。すなわち、被膜が均一に形成され、剥離部位が存在しない場合、もしくは被膜が僅かに不均一であるが、剥離部分が存在しない場合を○、被膜が不均一で、ピンホール状の剥離部位が存在する場合、もしくは被膜が不均一で、明確な剥離部位が存在する場合を×とした。
(9) Evaluation of adhesion of forsterite film The adhesion of forsterite film was judged from the state of the film. In other words, if the film is uniformly formed and there are no peeled areas, or if the film is slightly uneven but there are no peeled areas, ○, and if the film is uneven and there are pinhole-like peeled areas. The case where the film was peeled off or the film was non-uniform and there was a clear peeling area was rated as ×.
<実施例1>
 濃度2.0mol/Lのマグネシウムイオンを含む苦汁に、水酸化カルシウムスラリーを、反応後の水酸化マグネシウム濃度が1.2mol/Lになるように添加し、混合液を得た。混合液を600rpmで攪拌しながら323Kにて7.0時間反応させた。その後、フィルタープレスで濾過し、水洗し、乾燥して水酸化マグネシウムを得た。この水酸化マグネシウムに、塩化亜鉛(関東化学製、試薬特級)を焼成後の酸化マグネシウム中のZnが720ppmとなるように混合した後、ロータリーキルンにより1173Kで0.5時間焼成したのち粉砕し、実施例1の酸化マグネシウム粉末を得た。なお、焼成は、酸化マグネシウムのCAA40%が70~90秒の範囲となる条件で行った。
<Example 1>
Calcium hydroxide slurry was added to bittern containing magnesium ions at a concentration of 2.0 mol/L so that the magnesium hydroxide concentration after reaction was 1.2 mol/L to obtain a mixed solution. The mixture was stirred at 600 rpm and reacted at 323 K for 7.0 hours. Thereafter, it was filtered using a filter press, washed with water, and dried to obtain magnesium hydroxide. Zinc chloride (manufactured by Kanto Kagaku, reagent special grade) was mixed with this magnesium hydroxide so that the Zn content in the magnesium oxide after firing was 720 ppm, and the mixture was fired in a rotary kiln at 1173K for 0.5 hours, and then pulverized. Magnesium oxide powder of Example 1 was obtained. Note that the firing was performed under conditions such that the CAA of magnesium oxide was 40% in the range of 70 to 90 seconds.
<実施例2>
 塩化亜鉛(試薬特級)を焼成後の酸化マグネシウム中のZnが2250ppmとなるように混合した以外は、実施例1と同様にして、酸化マグネシウム粉末を得た。
<Example 2>
Magnesium oxide powder was obtained in the same manner as in Example 1, except that zinc chloride (special grade reagent) was mixed so that the Zn content in the magnesium oxide after firing was 2250 ppm.
<実施例3>
 塩化亜鉛(試薬特級)を焼成後の酸化マグネシウム中のZnが4300ppmとなるように混合した以外は、実施例1と同様にして、酸化マグネシウム粉末を得た。
<Example 3>
Magnesium oxide powder was obtained in the same manner as in Example 1, except that zinc chloride (special grade reagent) was mixed so that the Zn content in the magnesium oxide after firing was 4300 ppm.
<実施例4>
 濃度2.0mol/Lのマグネシウムイオンを含む苦汁に、水酸化カルシウムスラリーを、反応後の水酸化マグネシウム濃度が1.2mol/Lになるように添加し、混合液を得た。この混合液に塩化亜鉛(関東化学製、試薬特級)を焼成後の酸化マグネシウム中のZnが8800ppmとなるように混合した後、混合液を600rpmで攪拌しながら323Kにて7.0時間反応させ、その後フィルタープレスで濾過し、水洗し、乾燥して水酸化マグネシウムを得た。この水酸化マグネシウムをロータリーキルンにより1173Kで0.5時間焼成したのち粉砕し、実施例4の酸化マグネシウム粉末を得た。なお、焼成は、酸化マグネシウムのCAA40%が70~95秒の範囲となる条件で行った。
<Example 4>
Calcium hydroxide slurry was added to bittern containing magnesium ions at a concentration of 2.0 mol/L so that the magnesium hydroxide concentration after reaction was 1.2 mol/L to obtain a mixed solution. Zinc chloride (manufactured by Kanto Kagaku, reagent special grade) was mixed with this mixed solution so that the Zn content in the magnesium oxide after firing was 8800 ppm, and then the mixed solution was reacted at 323 K for 7.0 hours while stirring at 600 rpm. , and then filtered with a filter press, washed with water, and dried to obtain magnesium hydroxide. This magnesium hydroxide was fired in a rotary kiln at 1173K for 0.5 hours and then pulverized to obtain magnesium oxide powder of Example 4. Note that the firing was performed under conditions such that the CAA of magnesium oxide was 40% in the range of 70 to 95 seconds.
<実施例5>
 塩化亜鉛に代えて、酸化亜鉛(和光純薬製、試薬特級)を、焼成後の酸化マグネシウム中のZnが5250ppmとなるように混合した以外は、実施例4と同様にして、酸化マグネシウム粉末を得た。
<Example 5>
Magnesium oxide powder was prepared in the same manner as in Example 4, except that zinc oxide (manufactured by Wako Pure Chemical Industries, Ltd., reagent special grade) was mixed in place of zinc chloride so that the Zn content in the magnesium oxide after firing was 5250 ppm. Obtained.
<比較例1>
 塩化亜鉛(試薬特級)を混合しなかった以外は、実施例1と同様にして、酸化マグネシウム粉末を得た。
<Comparative example 1>
Magnesium oxide powder was obtained in the same manner as in Example 1, except that zinc chloride (special grade reagent) was not mixed.
 得られた実施例1~5及び比較例1の酸化マグネシウム粉末について、上記のとおり、含有成分等の測定を行い、また、これら酸化マグネシウム粉末を用いて得た方向性電磁鋼板の評価を実施した。結果を表1に示す。なお、表に示す以外の金属元素については、通常の不純物レベルの含有量であった。 Regarding the obtained magnesium oxide powders of Examples 1 to 5 and Comparative Example 1, the contained components etc. were measured as described above, and grain-oriented electrical steel sheets obtained using these magnesium oxide powders were evaluated. . The results are shown in Table 1. Note that the contents of metal elements other than those shown in the table were at normal impurity levels.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
 表1から明らかなように、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g以上の酸化マグネシウム(実施例1~5)を用いて形成したフォルステライト被膜は、(a)被膜の外観、(b)被膜の密着性について優れていることが明らかとなった。一方、水銀圧入式細孔分布測定による細孔のモード容積が1.3cm/g未満である酸化マグネシウム(比較例1)を用いて形成したフォルステライト被膜は、(a)被膜の外観、(b)被膜の密着性ともに劣っていた。 As is clear from Table 1, magnesium oxide ( It was revealed that the forsterite coatings formed using Examples 1 to 5) were excellent in (a) the appearance of the coating and (b) the adhesion of the coating. On the other hand, a forsterite coating formed using magnesium oxide (Comparative Example 1) with a pore mode volume of less than 1.3 cm 3 /g as measured by mercury intrusion pore distribution measurement has (a) appearance of the coating, ( b) Both the adhesion of the film was poor.
 以上のことから、本発明の焼鈍分離剤用酸化マグネシウムによれば、優れたフォルステライト被膜を有する方向性電磁鋼板を製造することができることが明らかとなった。 From the above, it has been revealed that the magnesium oxide for annealing separator of the present invention can produce a grain-oriented electrical steel sheet having an excellent forsterite coating.
 本発明によれば、被膜特性に優れた方向性電磁鋼板を提供することができる焼鈍分離剤用酸化マグネシウムを提供できる。 According to the present invention, it is possible to provide magnesium oxide for an annealing separator that can provide grain-oriented electrical steel sheets with excellent film properties.

Claims (6)

  1.  BET比表面積が12.0m/g以上30.0m/g以下であって、水銀圧入式細孔分布測定による細孔のモード径が0.1μm以上0.4μm未満であり、細孔のモード容積が1.3cm/g以上である焼鈍分離剤用酸化マグネシウム。 The BET specific surface area is 12.0 m 2 /g or more and 30.0 m 2 /g or less, the pore mode diameter measured by mercury intrusion pore distribution measurement is 0.1 μm or more and less than 0.4 μm, and the pore Magnesium oxide for an annealing separator having a mode volume of 1.3 cm 3 /g or more.
  2.  CAA40%が50秒以上170秒以下であり、Clの含有量が500ppm以下、体積基準の累積50%粒子径(D50)が0.5μm以上7.0μm以下である、請求項1に記載の焼鈍分離剤用酸化マグネシウム。 According to claim 1, the CAA40% is 50 seconds or more and 170 seconds or less, the Cl content is 500 ppm or less, and the volume-based cumulative 50% particle diameter (D 50 ) is 0.5 μm or more and 7.0 μm or less. Magnesium oxide for annealing separator.
  3.  Zn、Zr、Ni、Co、Mnの合計含有量が200ppm以上10000ppm以下である、請求項1または2に記載の焼鈍分離剤用酸化マグネシウム。 The magnesium oxide for an annealing separator according to claim 1 or 2, wherein the total content of Zn, Zr, Ni, Co, and Mn is 200 ppm or more and 10,000 ppm or less.
  4.  Znの含有量が200ppm以上10000ppm以下である、請求項1または2に記載の焼鈍分離剤用酸化マグネシウム。 The magnesium oxide for an annealing separator according to claim 1 or 2, wherein the content of Zn is 200 ppm or more and 10,000 ppm or less.
  5.  請求項1~4のいずれか一項に記載の焼鈍分離剤用酸化マグネシウムを含む焼鈍分離剤。 An annealing separator comprising magnesium oxide for an annealing separator according to any one of claims 1 to 4.
  6.  鋼板表面にSiO被膜を形成する工程と、
     請求項5に記載の焼鈍分離剤をSiO被膜の表面に塗布し、焼鈍することにより、鋼板表面にフォルステライト被膜を形成する工程と
    を含む、方向性電磁鋼板の製造方法。
    forming a SiO 2 film on the surface of the steel plate;
    A method for manufacturing a grain-oriented electrical steel sheet, comprising the step of forming a forsterite film on the surface of the steel sheet by applying the annealing separator according to claim 5 to the surface of the SiO 2 film and annealing.
PCT/JP2023/013053 2022-03-31 2023-03-30 Magnesium oxide for annealing separating agent, and grain-oriented electrical steel sheet WO2023190806A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001083848A1 (en) * 2000-05-01 2001-11-08 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate
WO2002034965A1 (en) * 2000-10-25 2002-05-02 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate
WO2009001883A1 (en) * 2007-06-27 2008-12-31 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate, and method for production thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001083848A1 (en) * 2000-05-01 2001-11-08 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate
WO2002034965A1 (en) * 2000-10-25 2002-05-02 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate
WO2009001883A1 (en) * 2007-06-27 2008-12-31 Tateho Chemical Industries Co., Ltd. Magnesium oxide particle aggregate, and method for production thereof

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