WO2015099203A1 - Method for preparing barium titanyl oxalate, method for preparing barium titanate, and barium titanate - Google Patents

Method for preparing barium titanyl oxalate, method for preparing barium titanate, and barium titanate Download PDF

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WO2015099203A1
WO2015099203A1 PCT/KR2013/010812 KR2013010812W WO2015099203A1 WO 2015099203 A1 WO2015099203 A1 WO 2015099203A1 KR 2013010812 W KR2013010812 W KR 2013010812W WO 2015099203 A1 WO2015099203 A1 WO 2015099203A1
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bto
barium
barium titanate
powder
dry
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French (fr)
Korean (ko)
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차경진
유수연
허지영
정원식
최연규
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삼성전기 주식회사
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/003—Titanates
    • C01G23/006—Alkaline earth titanates
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/41—Preparation of salts of carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/18—Carbonates
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C55/00—Saturated compounds having more than one carboxyl group bound to acyclic carbon atoms
    • C07C55/02—Dicarboxylic acids
    • C07C55/08—Malonic acid
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/28—Titanium compounds
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/45—Aggregated particles or particles with an intergrown morphology
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/51—Particles with a specific particle size distribution
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area

Definitions

  • a method for producing barium titanyl oxalate, a method for producing barium titanate, and barium titanate are disclosed. More specifically, the method for preparing barium titanyl oxalate which can improve the dry grinding efficiency to obtain a barium titanyl oxalate powder having a low bulk density, and has a high crystallinity due to a low content of aggregates and a necking ratio Disclosed are a method for producing barium titanate from which barium titanate can be obtained, and barium titanate produced by the method.
  • the barium titanate powder was conventionally manufactured by a solid phase reaction in which titanium dioxide (TiO 2 ) and barium carbonate (BaCO 3 ) were mixed and heat treated at a high temperature.
  • TiO 2 titanium dioxide
  • BaCO 3 barium carbonate
  • High purity / composition uniformity, fine grain / particle uniformity, non-aggregation / high dispersion, etc. are required according to high dielectric constant composition, dielectric thinning and high lamination), low temperature plasticization, high frequency and high performance.
  • Various synthesis methods are used for the preparation of barium titanate powder.
  • a coprecipitation method which is a kind of liquid phase method, to obtain a barium titanate powder having low manufacturing cost and a chemical uniformity, must be used.
  • a liquid raw material containing barium (Ba) and titanium (Ti) is brought into contact with oxalic acid (H 2 C 2 O 4 ) to make barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O].
  • oxalic acid H 2 C 2 O 4
  • barium titanyl oxalate BaTiO (C 2 O 4 ) 2 .4H 2 O.
  • the barium titanate (BaTiO 3 ) powder having an appropriate size is synthesized by heat treating the BTO at a high temperature.
  • barium titanate is inferior.
  • pores may be formed in the particles while abnormal grain growth occurs during the sintering process of the MLCC, which negatively affects the capacity and reliability of the MLCC.
  • Barium titanate is difficult to apply to a high capacity MLCC.
  • One embodiment of the present invention provides a method for producing barium titanyl oxalate which can improve dry grinding efficiency to obtain barium titanyl oxalate powder having a low bulk density.
  • Another embodiment of the present invention provides a method for producing barium titanate which can obtain barium titanate having high crystallinity due to a low content of aggregates and a necking ratio.
  • Another embodiment of the present invention provides a barium titanate that can be used in a small-ultra high capacity multilayer ceramic capacitor manufactured by the method for producing barium titanate.
  • BTO barium titanyl oxalate
  • the BTO dry grinding step provides a method for producing barium titanyl oxalate which is carried out until the bulk density of the dry pulverized BTO is 0.2 g / cm 3 or more and 0.50 g / cm 3 or less.
  • the barium compound solution is prepared by dissolving at least one barium compound selected from the group consisting of barium chloride (BaCl 2 ), barium nitrate (Ba (NO 3 ) 2 ) and barium perchlorate (Ba (ClO 4 ) 2 ) in water.
  • the titanium compound solution is prepared by dissolving at least one titanium compound of titanium oxychloride (TiOCl 2 ) and titanium tetrachloride (TiCl 4 ) in water, and the oxalic acid solution is prepared by dissolving oxalic acid in water. It may be.
  • the BTO synthesis step may be performed at a synthesis temperature of 20 ⁇ 100 °C.
  • the BTO dry grinding step may be performed using at least one grinder selected from the group consisting of a hammer mill, an air flow classification grinder (ACM) and a jet mill.
  • ACM air flow classification grinder
  • the dry milled BTO may have a particle size of 2.5 ⁇ m or less (PSA D50) and a particle size of 8.0 ⁇ m or less (PSA D90).
  • the method for producing barium titanyl oxalate, between the BTO synthesis step and the BTO wet grinding step, the step of ripening the synthesized BTO, the step of filtering the aged BTO, and the filtered BTO excess may further include washing with water.
  • Barium titanate comprising a step of synthesizing barium titanate [BaTiO 3 ] (hereinafter referred to simply as BT) by heat-treating BTO prepared according to the method for preparing barium titanyl oxalate at 800 to 1000 ° C. (BT synthesis step). It provides a method of manufacturing.
  • the method for producing barium titanate may further include, after the BT synthesis step, pulverizing the synthesized BT (BT crushing step).
  • the barium titanate powder made of barium titanate may include an aggregate of 10 wt% or less.
  • the method for producing barium titanyl oxalate by introducing a dry grinding process, it is possible to achieve the uniformity of the barium titanyl oxalate and to raise the level of grinding and to improve productivity.
  • Figure 1a is a view for explaining the action and effect of the BTO dry grinding step in the method for producing barium titanyl oxalate (BTO) according to an embodiment of the present invention.
  • Figure 1b is a view for explaining the problem that occurs when there is no BTO dry grinding step, as in the conventional method for producing barium titanyl oxalate (BTO).
  • FIG. 3 shows a material that does not pass through the filter when the BT dispersion is filtered with a filter after preparing the BT dispersion by dispersing BT prepared according to the BT manufacturing method of some examples and comparative examples in alcohol, that is, Agglomerates).
  • FIG. 4 is a SEM photograph of a BT manufactured according to the BT manufacturing method of some examples and comparative examples.
  • Method for producing barium titanyl oxalate comprises the steps of preparing a barium compound solution, titanium compound solution and oxalic acid solution (raw material preparation step), the barium compound solution and the titanium compound solution to the oxalic acid Contacting the solution to synthesize barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O] (hereinafter referred to simply as BTO) (BTO synthesis step), and wet grinding the synthesized BTO. (BTO wet grinding step), drying the wet milled BTO to obtain a BTO powder (BTO drying step), and the step of dry grinding the dried BTO (BTO dry grinding step).
  • the barium compound solution is prepared by dissolving at least one barium compound selected from the group consisting of barium chloride (BaCl 2 ), barium nitrate (Ba (NO 3 ) 2 ) and barium perchlorate (Ba (ClO 4 ) 2 ) in water. It may be one.
  • the concentration of the barium compound solution may be 0.2 ⁇ 2.0 mol / L. When the concentration of the barium compound solution is within the above range, the productivity of barium titanate (BT) to be described later is high relative to the volume of the barium compound solution, and the barium compound does not precipitate.
  • the titanium compound solution may be prepared by dissolving at least one titanium compound of titanium oxychloride (TiOCl 2 ) and titanium tetrachloride (TiCl 4 ) in water.
  • the concentration of the titanium compound solution may be 0.2 ⁇ 2.0 mol / L. When the concentration of the titanium compound solution is within the above range, the productivity of BT relative to the volume of the titanium compound solution is high, and the titanium compound does not precipitate.
  • the oxalic acid solution may be prepared by dissolving oxalic acid (H 2 C 2 O 4 ) in water.
  • the oxalic acid solution may be used in an amount larger than that of the barium compound solution or the titanium compound solution.
  • the concentration range of the oxalic acid solution may be 0.2 ⁇ 5.0 mol / L.
  • the BTO synthesis step may be carried out at a synthesis temperature of 20 ⁇ 100 °C, for example, 50 ⁇ 90 °C.
  • the productivity of the BTO is high and the synthesized BTO can be prevented from being re-decomposed.
  • the barium compound solution and the titanium compound solution may be simultaneously or sequentially contacted with the oxalic acid solution in the form of a mixed solution or separately.
  • the contact may be performed by nozzle spraying, and the contact time may be 1 to 3 hours. This contact time can be achieved by adjusting the injection speed of the nozzle.
  • the injection nozzle may use a hydraulic or two-fluid nozzle depending on the flow of the fluid, and the use of the hydraulic nozzle may be more advantageous in terms of convenience or in obtaining a uniform precipitate.
  • a full cone, a hollow cone, a flat, or the like may be used as the hydraulic nozzle.
  • the synthesized BTO may be aged (BTO ripening step), filtered (BTO filtration step), and then washed with water (BTO washing step).
  • BTO ripening step may be advantageous in terms of productivity to proceed for 0.5 to 2 hours.
  • filtration means the process of separating only solid-phase BTO from the BTO containing BTO slurry using a centrifuge, a filter press, etc. specifically. Thereafter, the filtered BTO may be washed with excess water until the pH of the washing liquid becomes neutral.
  • the washed BTO may be dried at 80 to 150 ° C. for 8 to 12 hours.
  • the wet grinding refers to grinding the BTO with a predetermined medium in a wet grinding machine such as a beads mill, a ball mill, an attrition mill, and the like.
  • the medium means an organic medium such as alcohol or water such as deionized water, and the use of an organic medium is advantageous in terms of crushing efficiency or particle size, but has a disadvantage of increasing cost. This simplifies the process and has the advantage of reducing costs.
  • water used as the medium, its amount may be 1 to 10 parts by weight based on 1 part by weight of BTO.
  • the amount of water used is within the above range, the viscosity is moderate, so that grinding is easy, and the productivity of BTO is high relative to the volume of water.
  • the grinding time needs to be appropriately controlled due to a difference in grinding force depending on the grinding equipment, and may be 10 to 300 minutes when a bead mill is used. By controlling the grinding time as described above, the particle size of the final product BT powder can be properly adjusted. Nitrogen-containing additives such as ammonia may be added during this wet grinding process, thereby reducing acidity of the powder due to acidification of the mixture before and after grinding, high viscosity of the BTO slurry after grinding, and the presence of chlorine ions in the synthesized BTO. It can be solved partially or completely.
  • the wet milled BTO is dried at a temperature below 400 ° C. to remove the used medium (BTO drying step).
  • BTO drying step As a result, dried BTO powder is obtained.
  • the drying temperature should be above the boiling point of the medium in order to evaporate and remove the used medium.
  • BTO dry milling step a dry pulverized BTO powder is obtained.
  • the BTO dry grinding step is performed until the bulk density of the dry milled BTO is 0.2 g / cm 3 or more and 0.50 g / cm 3 or less. Accordingly, the ratio of the aggregates and the necking ratio in the barium titanate powder prepared by heat-treating the dry pulverized BTO powder may be reduced, and during the heat treatment of the BTO (that is, during the BT synthesis step), the BTO is decomposed.
  • the generated gases CO, CO 2 , H 2 O, etc.
  • necking means that when the two or more particles are bonded to each other, a constricted portion is formed at the boundary thereof.
  • the dry milled BTO may have a particle size of 2.5 ⁇ m or less (PSA D50) and a particle size of 8.0 ⁇ m or less (PSA D90).
  • particle diameters (PSA D10, PSA D50 and PSA D90) are measured by a particle size analyzer (Malvern's Mastersizer 2000).
  • the bulk density of the dry milled BTO powder is reduced to 0.50 g / cm 3 or less, so that the dry milled BTO powder has a low formation rate of aggregates, thereby allowing each particle to be formed.
  • the ratio of being separated from each other increases.
  • the bulk density of the dry pulverized BTO powder is reduced to less than 0.2g / cm 3 , the fine BTO is present in a reaggregated state without being separated from each other due to the result of the formation of aggregates in the BT powder during heat treatment Pore is present, the BTO powder is present as a particulate has a problem that the grain growth is slow due to the slow diffusion rate between BTO particles during heat treatment.
  • the dry pulverized BTO powder that is, BTO powder having a bulk density of 0.2 g / cm 3 or more and 0.5 g / cm 3 or less
  • BT powder having a high ratio of the synthesized BT particles in a state in which they are separated from each other Will form.
  • the BT powder is then applied to MLCC. That is, the MLCC is manufactured by disposing the BT powder between the two electrode layers 10 to form the dielectric layer 20.
  • the dielectric layer 20 includes BT particles which are regularly arranged without aggregation with each other at a high ratio.
  • the MLCC is sintered.
  • the BT particles of the dielectric layer 20 are crystallized to form a crystal structure without voids.
  • Figure 1a illustrates that the BTO dry grinding step has the action and effect of forming a high crystallinity BT.
  • the dry milled BTO powder is present with at least some of the BTO particles forming aggregates. Accordingly, when the dry pulverized BTO powder is heat-treated, at least some of the synthesized BT particles form BT powder in a state in which aggregates are formed. In addition, the BT powder has voids that are a result of the formation of aggregates.
  • the BT powder is then applied to MLCC. That is, the MLCC is manufactured by disposing the BT powder between two electrode layers 10 to form a dielectric layer 20 '. In this case, the dielectric layer 20 ′ contains a high proportion of BT particles aggregated and irregularly arranged together.
  • FIG. 1B illustrates a problem in which the low crystallinity BT is formed when the BTO dry grinding step is not present.
  • the BTO dry grinding step may be performed using at least one grinder selected from the group consisting of a hammer mill, an air classifying mill (ACM) and a jet mill.
  • ACM air classifying mill
  • the rotor rotational speed of the hammer mill and the air classifier, and the air pressure of the jet mill can be appropriately adjusted so that the bulk density of the dry milled BTO is 0.2g / cm 3 or more and 0.50g / cm 3 or less.
  • the BTO powder is charged into a heating furnace, followed by heat treatment at 800 to 1000 ° C. to synthesize barium titanate [BaTiO 3 ] (hereinafter, simply referred to as BT).
  • BT barium titanate
  • PSA D50 target particle size
  • impurities CO, CO 2 , H 2 O, etc.
  • water and / or carbon may be removed.
  • the temperature increase rate from the drying temperature of the BTO drying step to the heat treatment temperature of the BT synthesis step may be 0.5 ⁇ 10 °C / min, for example 1 ⁇ 5 °C / min. If the temperature increase rate is within the above range, the productivity of BT is high, the temperature distribution is uniform, and the particle size of the BT powder is uniform.
  • BT powder of several tens nm to hundreds of nm is obtained by removing water and excess carbon dioxide gas which are present as crystal water inside the BTO crystal through the process as in Schemes 2 to 4 below. Can be.
  • Sagger or Tray may be used as a heating furnace for heat treatment of the dried BTO powder.
  • Sagger means a refractory soil container.
  • the sagger may be, for example, a cube-shaped container having a bottom surface of a square shape.
  • the BT produced through the BT synthesis step is pulverized to obtain BT powder (BT crushing step).
  • BT grinding step may be performed by wet grinding using a grinder such as a beads mill, an attention mill, or a ball mill with a predetermined medium, or a jet mill ( It may also be carried out by dry grinding using friction between the raw materials or friction with the pulverizer without using a medium such as a jet mill or a disk mill.
  • the pulverization step is for resolving the agglomeration of particles of barium titanate.
  • a drying step is additionally required, but it is not necessary to use a particularly limited facility for drying.
  • Another aspect of the present invention provides a barium titanate prepared by the method for producing barium titanate including the method for producing barium titanyl oxalate.
  • the barium titanate powder made of barium titanate may include an aggregate of 10 wt% or less.
  • aggregate means a predetermined amount (for example, 5g) of BT powder in alcohol (for example, 150ml of ethanol) to prepare a BT dispersion, and then, the BT dispersion using a metering pump 14
  • the filter is injected into a filter having a ⁇ m mesh size, it means a substance that cannot pass through the filter.
  • the BTO slurry prepared above was filtered with a centrifugal separator, and washed with excess water so that the pH of the washing liquid was 3 or more to obtain a washed BTO.
  • BTO 50 kg of the BTO, 250 kg of deionized water, and 0.5 kg of 29% by volume ammonia water (8. 4 mol parts relative to 100 mol parts of BTO) were added to a mixing tank and stirred to form a slurry. At this time, the pH of the slurry was 4.5. Thereafter, the BTO was wet milled with a 20 L horizontal beads mill (medium: deionized water) such that the maximum particle size was 5 ⁇ m or less. After grinding, the slurry had a pH of 5.1 and a viscosity of 1800 cP. Thus obtained BTO slurry was dried in an oven at a temperature of 200 °C for 12 hours to prepare a BTO powder.
  • the dried BTO was hammered at a speed of 4 kg / hr in a hammer mill (Daesung Powder System, DGHSM-2), air classifier (Best PTS Co., Ltd., BCM-T1-00) or jet mill (SEISHIN ENTERPRISE, STJ-560). It was injected into the dry grinding. As a result, dry milled BTO was obtained.
  • the rotor rotation speed of the hammer mill, the rotor rotation speed of the air classifier, and the air pressure of the jet mill adopted in the above Examples and Comparative Examples are shown in Table 1, respectively.
  • the dry pulverized BTO powder was put into an electric furnace (WonJun, RHK), and then heat-treated at 930 ° C. for 3 hours. As a result, BT powder was obtained. Thereafter, the BT powder was wet-pulverized for 30 minutes at a speed of 5 m / s (ie, 1500 rpm) with a 20 L horizontal beads mill (medium: deionized water). The BT slurry formed after the wet grinding was dried in an oven at 150 ° C. for 24 hours. As a result, BT powder was obtained.
  • the bulk density of the dry milled BTO obtained in each of the above Examples and Comparative Examples was measured, and the results are shown in Table 2 below. Specifically, the bulk density of the dry milled BTO (ie, BTO powder) was measured according to the ISO 23145-1 standard.
  • the BTO prepared in Examples 1 to 5 was found to have a smaller particle size (PSA D10, PSA D50 and PSA D90) than the BTO prepared in Comparative Examples 1 to 4.
  • the particle diameter (SEM D50) is the long axis and shortening of the barium titanate particles using an image analysis program (ImagePro Plus ver 4.5 of Mediacybernetics, Inc.) after taking an image using a scanning electron microscope (SEM, Jeol JSM-7400F)
  • SEM, Jeol JSM-7400F scanning electron microscope
  • the content of aggregates in the BT powder synthesized in each of Examples and Comparative Examples was analyzed, and the results are shown in Table 3 below. Specifically, after dispersing the BT powder synthesized in each of the above Examples and Comparative Examples in 150ml of ethanol to prepare a BT dispersion, the BT dispersion using a metering pump (Masterflex, 7528-10S) of 14 ⁇ m mesh size The filter was injected into a stainless steel mesh and filtered. Subsequently, the content (W R ) of the substance remaining without passing through the filter was measured in units of 'g'. Then, the content of the aggregate was calculated according to the following equation (1).
  • the BT prepared in Examples 1 to 5 has a higher crystallinity (k-factor and c / a) and a smaller particle size (SEM D50) than the BT prepared in Comparative Examples 1 to 4, The specific surface area was large and the content of aggregate was found to be very small.
  • FIG. 2 SEM images of the BTO powder before and after the dry grinding were taken and the results are shown in FIG. 2.
  • (a) is the BTO powder before dry grinding prepared in Examples 1 to 5 and Comparative Examples 1 to 4
  • (b) is the BTO powder after dry grinding prepared in Comparative Example 3
  • (c) Is BTO powder after dry grinding prepared in Example 2
  • (d) is BTO powder after dry grinding prepared in Example 5.
  • the BTO powders ((c) and (d) after dry grinding prepared in Examples 2 and 5 are BTO powders ((a)) before dry grinding and BTO after dry grinding prepared in Comparative Example 3
  • the content of aggregates was found to be significantly lower than the powder ((b)).
  • the BT powders ((c) and (d) after dry grinding prepared in Examples 2 and 5 are BT powders ((a)) before dry grinding and BT after dry grinding prepared in Comparative Example 3
  • the content of aggregates was found to be significantly lower than the powder ((b)).
  • FIG. 4 SEM pictures of the BT powder prepared by heat-treating the BTO powder before and after the dry grinding were taken, and the results are shown in FIG. 4.
  • (a) is a BT powder prepared by directly heat-treating the BTO powder before dry grinding prepared in Examples 1 to 5 and Comparative Examples 1 to 4 without dry grinding
  • (b) is prepared in Comparative Example 3 Is a BT powder prepared in Example 2
  • (c) is a BT powder prepared in Example 2
  • (d) is a BT powder prepared in Example 5.
  • the BT powders ((c) and (d)) prepared in Examples 2 and 5 are BT powders ((a)) prepared by directly heat-treating the BTO powder before dry grinding and a comparative example. Compared with the BT powder prepared in (3) (b), the particle size was similar to each other, but the content of aggregates was found to be remarkably small.

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Abstract

A method for preparing barium titanyl oxalate, a method for preparing barium titanate, and barium titanate are disclosed. The disclosed method for preparing barium titanyl oxalate comprises: a step for preparing a barium compound solution, a titanium compound solution, and an oxalic acid solution (a raw material solution preparation step); a step for making the barium compound solution and the titanium compound solution come into contact with the oxalic acid solution so as to synthesize barium titanyl oxalate [BaTiO(C2O4)2·4H2O] (hereinafter, simply referred to as BTO) (a BTO synthesis step); a step for wet milling the synthesized BTO (a BTO wet milling step); a step for drying the wet milled BTO so as to obtain BTO powder (a BTO drying step); and a step for dry milling the dried BTO (a BTO dry milling step), wherein the BTO dry milling step is carried out until the bulk density of the dry milled BTO is 0.2g/cm3 - 0.50g/cm3.

Description

바륨티타닐옥살레이트의 제조방법, 티탄산바륨의 제조방법, 및 티탄산바륨Method for producing barium titanyl oxalate, method for producing barium titanate, and barium titanate
바륨티타닐옥살레이트의 제조방법, 티탄산바륨의 제조방법, 및 티탄산바륨이개시된다. 보다 상세하게는, 건식분쇄 효율을 향상시켜 부피 밀도(bulk density)가 낮은 바륨티타닐옥살레이트 분말을 얻을 수 있는 바륨티타닐옥살레이트의 제조방법, 응집체의 함량 및 네킹 비율이 낮아 결정성이 높은 티탄산바륨을 얻을 수 있는 티탄산바륨의 제조방법, 및 그 방법에 의해 제조된 티탄산바륨이 개시된다.A method for producing barium titanyl oxalate, a method for producing barium titanate, and barium titanate are disclosed. More specifically, the method for preparing barium titanyl oxalate which can improve the dry grinding efficiency to obtain a barium titanyl oxalate powder having a low bulk density, and has a high crystallinity due to a low content of aggregates and a necking ratio Disclosed are a method for producing barium titanate from which barium titanate can be obtained, and barium titanate produced by the method.
티탄산바륨 분말은 종래에는 이산화티탄(TiO2)과 탄산바륨(BaCO3)을 혼합하여 고온에서 열처리하는 고상반응에 의해 제조되었지만, 최근에는 적층 세라믹 콘덴서(multi layer ceramic condenser: MLCC)의 소형 대용량화(고유전율 조성, 유전체 박층화 및 고적층화), 저온 소성화, 고주파 및 고성능화 등에 따라, 고순도/조성 균일성, 미립/입도 균일성, 非응집성/고분산성 등이 요구되어 고상법뿐만 아니라 액상법 및 기상법 등 다양한 합성법이 티탄산바륨 분말의 제조를 위해 사용되고 있다. 그러나, 티탄산바륨 분말의 대량 생산을 위해서는, 제조비용이 저렴하고 화학적으로 균일한 티탄산바륨 분말을 얻을 수 있는 액상법의 일종인 공침법이 사용되어야 한다.The barium titanate powder was conventionally manufactured by a solid phase reaction in which titanium dioxide (TiO 2 ) and barium carbonate (BaCO 3 ) were mixed and heat treated at a high temperature. High purity / composition uniformity, fine grain / particle uniformity, non-aggregation / high dispersion, etc. are required according to high dielectric constant composition, dielectric thinning and high lamination), low temperature plasticization, high frequency and high performance. Various synthesis methods are used for the preparation of barium titanate powder. However, for mass production of barium titanate powder, a coprecipitation method, which is a kind of liquid phase method, to obtain a barium titanate powder having low manufacturing cost and a chemical uniformity, must be used.
공침법에서는, 바륨(Ba)과 티타늄(Ti)을 함유하는 액상 원료를 옥살산(H2C2O4)과 접촉시켜 바륨티타닐옥살레이트[BaTiO(C2O4)2·4H2O](이하, 간단히 BTO라고 함)를 형성한 후, 이 BTO를 높은 온도에서 열처리함으로써 적정 크기를 갖는 티탄산바륨(BaTiO3) 분말을 합성한다. 이러한 공침법은 침전된 BTO를 적절한 크기로 분쇄하지 않을 경우, BTO의 하소후 형성된 티탄산바륨(BT)은 입자간 강하게 응집되어, 추후 BT의 분쇄과정에서 입자간 분리와 함께 미분이 다량 발생하게 되고, BT의 입도분포가 넓어지며 결정성이 저하되는 문제점이 있다. 이에 따라, 상기 특성상 BTO의 미립화가 요구된다. 따라서, 종래의 공침법에서는 분쇄효율이 높은 습식분쇄공정을 채택하여 사용하고 있으나, 상기 습식분쇄공정 후 건조공정이 진행됨에 따라 BTO 입자들이 서로 응집하여 BTO 분말 중 응집체의 비율이 증가하고, 이에 따라 최종 제품인 티탄산바륨의 결정성이 떨어지는 문제점이 있다. 또한, 상기 티탄산바륨을 MLCC에 적용할 경우, MLCC의 소결과정에서 비정상 입자성장(abnormal grain growth)이 발생하면서 입자내부에 기공이 형성될 수 있으며, 이는 MLCC의 용량 및 신뢰성에 부정적인 영향을 미쳐서 상기 티탄산바륨을 고용량의 MLCC에 적용하기 어려운 문제점이 있다.In the coprecipitation method, a liquid raw material containing barium (Ba) and titanium (Ti) is brought into contact with oxalic acid (H 2 C 2 O 4 ) to make barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O]. After forming (hereinafter simply referred to as BTO), the barium titanate (BaTiO 3 ) powder having an appropriate size is synthesized by heat treating the BTO at a high temperature. In this coprecipitation method, when the precipitated BTO is not pulverized to an appropriate size, barium titanate (BT) formed after calcination of BTO is strongly aggregated between particles, so that a large amount of fine powder is generated along with the separation between particles in the crushing process of BT. , BT has a problem that the particle size distribution of the BT becomes wider and the crystallinity is lowered. Accordingly, in view of the above characteristics, atomization of BTO is required. Therefore, in the conventional coprecipitation method, a wet grinding process having a high grinding efficiency is adopted and used, but as the drying process is performed after the wet grinding process, the BTO particles agglomerate with each other, thereby increasing the proportion of aggregates in the BTO powder. There is a problem that the crystallinity of the final product barium titanate is inferior. In addition, when the barium titanate is applied to the MLCC, pores may be formed in the particles while abnormal grain growth occurs during the sintering process of the MLCC, which negatively affects the capacity and reliability of the MLCC. Barium titanate is difficult to apply to a high capacity MLCC.
본 발명의 일 구현예는 건식분쇄 효율을 향상시켜 부피 밀도(bulk density)가 낮은 바륨티타닐옥살레이트 분말을 얻을 수 있는 바륨티타닐옥살레이트의 제조방법을 제공한다.One embodiment of the present invention provides a method for producing barium titanyl oxalate which can improve dry grinding efficiency to obtain barium titanyl oxalate powder having a low bulk density.
본 발명의 다른 구현예는 응집체의 함량 및 네킹 비율이 낮아 결정성이 높은 티탄산바륨을 얻을 수 있는 티탄산바륨의 제조방법을 제공한다.Another embodiment of the present invention provides a method for producing barium titanate which can obtain barium titanate having high crystallinity due to a low content of aggregates and a necking ratio.
본 발명의 또 다른 구현예는 상기 티탄산바륨의 제조방법에 의해 제조된, 소형-초고용량 적층형 세라믹 컨덴서에 사용이 가능한 티탄산바륨을 제공한다.Another embodiment of the present invention provides a barium titanate that can be used in a small-ultra high capacity multilayer ceramic capacitor manufactured by the method for producing barium titanate.
본 발명의 일 측면은,One aspect of the invention,
바륨 화합물 용액, 티탄 화합물 용액 및 옥살산 용액을 제조하는 단계(원료 용액 제조단계); Preparing a barium compound solution, a titanium compound solution, and an oxalic acid solution (raw material solution preparing step);
상기 바륨 화합물 용액과 상기 티탄 화합물 용액을 상기 옥살산 용액과 접촉시켜 바륨티타닐옥살레이트[BaTiO(C2O4)2·4H2O](이하, 간단히 BTO라고 함)를 합성하는 단계(BTO 합성단계); Contacting the barium compound solution and the titanium compound solution with the oxalic acid solution to synthesize barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O] (hereinafter simply referred to as BTO). step);
상기 합성된 BTO를 습식분쇄하는 단계(BTO 습식분쇄단계);Wet grinding the synthesized BTO (BTO wet grinding step);
상기 습식분쇄된 BTO를 건조하여 BTO 분말을 얻는 단계(BTO 건조단계); 및Drying the wet milled BTO to obtain a BTO powder (BTO drying step); And
상기 건조된 BTO를 건식분쇄하는 단계(BTO 건식분쇄단계)를 포함하고,Dry grinding the dried BTO (BTO dry grinding step),
상기 BTO 건식분쇄단계는 상기 건식분쇄된 BTO의 부피 밀도(bulk density)가 0.2g/cm3 이상 0.50g/cm3 이하로 될 때까지 실시되는 바륨티타닐옥살레이트의 제조방법을 제공한다.The BTO dry grinding step provides a method for producing barium titanyl oxalate which is carried out until the bulk density of the dry pulverized BTO is 0.2 g / cm 3 or more and 0.50 g / cm 3 or less.
상기 바륨 화합물 용액은 염화바륨(BaCl2), 질산바륨(Ba(NO3)2) 및 과염소산바륨(Ba(ClO4)2)으로 이루어진 군으로부터 선택된 적어도 1종의 바륨 화합물을 물에 용해시켜 제조한 것이고, 상기 티탄 화합물 용액은 옥시염화티탄(TiOCl2) 및 사염화티탄(TiCl4) 중 적어도 1종의 티탄 화합물을 물에 용해시켜 제조한 것이고, 상기 옥살산 용액은 옥살산을 물에 용해시켜 제조한 것일 수 있다.The barium compound solution is prepared by dissolving at least one barium compound selected from the group consisting of barium chloride (BaCl 2 ), barium nitrate (Ba (NO 3 ) 2 ) and barium perchlorate (Ba (ClO 4 ) 2 ) in water. The titanium compound solution is prepared by dissolving at least one titanium compound of titanium oxychloride (TiOCl 2 ) and titanium tetrachloride (TiCl 4 ) in water, and the oxalic acid solution is prepared by dissolving oxalic acid in water. It may be.
상기 BTO 합성단계는 20~100℃의 합성온도에서 수행될 수 있다.The BTO synthesis step may be performed at a synthesis temperature of 20 ~ 100 ℃.
상기 BTO 건식분쇄단계는 해머밀, 기류분급분쇄기(ACM) 및 제트밀로 이루어진 군으로부터 선택된 적어도 1종의 분쇄기를 사용하여 실시될 수 있다.The BTO dry grinding step may be performed using at least one grinder selected from the group consisting of a hammer mill, an air flow classification grinder (ACM) and a jet mill.
상기 건식분쇄된 BTO는 2.5㎛ 이하의 입경(PSA D50) 및 8.0㎛ 이하의 입경(PSA D90)을 가질 수 있다.The dry milled BTO may have a particle size of 2.5 μm or less (PSA D50) and a particle size of 8.0 μm or less (PSA D90).
상기 바륨티타닐옥살레이트의 제조방법은, 상기 BTO 합성단계와 상기 BTO 습식분쇄단계 사이에, 상기 합성된 BTO를 숙성하는 단계, 상기 숙성된 BTO를 여과하는 단계, 및 상기 여과된 BTO를 과량의 물로 세정하는 단계를 더 포함할 수 있다.The method for producing barium titanyl oxalate, between the BTO synthesis step and the BTO wet grinding step, the step of ripening the synthesized BTO, the step of filtering the aged BTO, and the filtered BTO excess The method may further include washing with water.
본 발명의 다른 측면은,Another aspect of the invention,
상기 바륨티타닐옥살레이트의 제조방법에 따라 제조된 BTO를 800~1000℃에서 열처리하여 티탄산바륨[BaTiO3](이하, 간단히 BT라고 함)을 합성하는 단계(BT 합성단계)를 포함하는 티탄산바륨의 제조방법을 제공한다.Barium titanate comprising a step of synthesizing barium titanate [BaTiO 3 ] (hereinafter referred to simply as BT) by heat-treating BTO prepared according to the method for preparing barium titanyl oxalate at 800 to 1000 ° C. (BT synthesis step). It provides a method of manufacturing.
상기 티탄산바륨의 제조방법은, 상기 BT 합성단계 이후에, 상기 합성된 BT를 분쇄하는 단계(BT 분쇄단계)를 더 포함할 수 있다.The method for producing barium titanate may further include, after the BT synthesis step, pulverizing the synthesized BT (BT crushing step).
본 발명의 또 다른 측면은,Another aspect of the invention,
상기 티탄산바륨의 제조방법에 의해 제조된 티탄산바륨을 제공한다.It provides barium titanate prepared by the method for producing barium titanate.
상기 티탄산바륨으로 이루어진 티탄산바륨 분말이 10중량% 이하의 응집체를 포함할 수 있다.The barium titanate powder made of barium titanate may include an aggregate of 10 wt% or less.
본 발명의 일 구현예에 따른 바륨티타닐옥살레이트의 제조방법에 의하면, 건식분쇄공정을 도입함으로써, 바륨티타닐옥살레이트의 분쇄 균일화 및 분쇄수준 상향화를 달성하고 생산성을 향상시킬 수 있다.According to the method for producing barium titanyl oxalate according to the embodiment of the present invention, by introducing a dry grinding process, it is possible to achieve the uniformity of the barium titanyl oxalate and to raise the level of grinding and to improve productivity.
본 발명의 다른 구현예에 따른 티탄산바륨의 제조방법에 의하면, 응집체의 함량 및 네킹 비율이 낮아 결정성이 높은 티탄산바륨을 얻을 수 있다.According to the method for producing barium titanate according to another embodiment of the present invention, it is possible to obtain barium titanate having high crystallinity due to a low content of aggregates and a necking ratio.
도 1a는 본 발명의 일 구현예 따른 바륨티타닐옥살레이트(BTO)의 제조방법에서, BTO 건식분쇄단계의 작용 및 효과를 설명하기 위한 도면이다.Figure 1a is a view for explaining the action and effect of the BTO dry grinding step in the method for producing barium titanyl oxalate (BTO) according to an embodiment of the present invention.
도 1b는 종래의 바륨티타닐옥살레이트(BTO)의 제조방법에서와 같이, BTO 건식분쇄단계가 없을 경우 발생하는 문제점을 설명하기 위한 도면이다.Figure 1b is a view for explaining the problem that occurs when there is no BTO dry grinding step, as in the conventional method for producing barium titanyl oxalate (BTO).
도 2는 일부 실시예 및 비교예의 BTO 제조방법에 따라 제조된 BTO의 SEM 사진이다.2 is a SEM photograph of BTO prepared according to the BTO preparation method of some examples and comparative examples.
도 3은 일부 실시예 및 비교예의 BT 제조방법에 따라 제조된 BT를 알코올에 분산시켜 BT 분산액을 제조한 후 상기 BT 분산액을 필터로 여과한 경우, 상기 필터를 통과하지 못하고 남아있는 물질(즉, 응집체)을 보여주는 사진이다.FIG. 3 shows a material that does not pass through the filter when the BT dispersion is filtered with a filter after preparing the BT dispersion by dispersing BT prepared according to the BT manufacturing method of some examples and comparative examples in alcohol, that is, Agglomerates).
도 4는 일부 실시예 및 비교예의 BT 제조방법에 따라 제조된 BT의 SEM 사진이다.4 is a SEM photograph of a BT manufactured according to the BT manufacturing method of some examples and comparative examples.
도 5는 일부 실시예 및 비교예의 BT 제조방법에 따라 제조된 BT의 XRD 스펙트럼이다.5 is an XRD spectrum of BT prepared according to the BT preparation method of some examples and comparative examples.
이하, 본 발명의 일 구현예에 따른 바륨티타닐옥살레이트의 제조방법 및 티탄산바륨의 제조방법을 상세히 설명한다.Hereinafter, a method of preparing barium titanyl oxalate and a method of preparing barium titanate according to an embodiment of the present invention will be described in detail.
본 발명의 일 구현예에 따른 바륨티타닐옥살레이트의 제조방법은 바륨 화합물 용액, 티탄 화합물 용액 및 옥살산 용액을 제조하는 단계(원료 용액 제조단계), 상기 바륨 화합물 용액과 상기 티탄 화합물 용액을 상기 옥살산 용액과 접촉시켜 바륨티타닐옥살레이트[BaTiO(C2O4)2·4H2O](이하, 간단히 BTO라고 함)를 합성하는 단계(BTO 합성단계), 상기 합성된 BTO를 습식분쇄하는 단계(BTO 습식분쇄단계), 상기 습식분쇄된 BTO를 건조하여 BTO 분말을 얻는 단계(BTO 건조단계), 및 상기 건조된 BTO를 건식분쇄하는 단계(BTO 건식분쇄단계)를 포함한다.Method for producing barium titanyl oxalate according to an embodiment of the present invention comprises the steps of preparing a barium compound solution, titanium compound solution and oxalic acid solution (raw material preparation step), the barium compound solution and the titanium compound solution to the oxalic acid Contacting the solution to synthesize barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O] (hereinafter referred to simply as BTO) (BTO synthesis step), and wet grinding the synthesized BTO. (BTO wet grinding step), drying the wet milled BTO to obtain a BTO powder (BTO drying step), and the step of dry grinding the dried BTO (BTO dry grinding step).
상기 바륨 화합물 용액은 염화바륨(BaCl2), 질산바륨(Ba(NO3)2) 및 과염소산바륨(Ba(ClO4)2)으로 이루어진 군으로부터 선택된 적어도 1종의 바륨 화합물을 물에 용해시켜 제조한 것일 수 있다. 상기 바륨 화합물 용액의 농도는 0.2~2.0 mol/L일 수 있다. 상기 바륨 화합물 용액의 농도가 상기 범위이내이면, 상기 바륨 화합물 용액의 부피 대비 후술하는 티탄산바륨(BT)의 생산성이 높으며, 바륨 화합물이 석출되지 않는다. The barium compound solution is prepared by dissolving at least one barium compound selected from the group consisting of barium chloride (BaCl 2 ), barium nitrate (Ba (NO 3 ) 2 ) and barium perchlorate (Ba (ClO 4 ) 2 ) in water. It may be one. The concentration of the barium compound solution may be 0.2 ~ 2.0 mol / L. When the concentration of the barium compound solution is within the above range, the productivity of barium titanate (BT) to be described later is high relative to the volume of the barium compound solution, and the barium compound does not precipitate.
상기 티탄 화합물 용액은 옥시염화티탄(TiOCl2) 및 사염화티탄(TiCl4) 중 적어도 1종의 티탄 화합물을 물에 용해시켜 제조한 것일 수 있다. 상기 티탄 화합물 용액의 농도는 0.2~2.0 mol/L일 수 있다. 상기 티탄 화합물 용액의 농도가 상기 범위이내이면, 상기 티탄 화합물 용액의 부피 대비 BT의 생산성이 높으며, 티탄 화합물이 석출되지 않는다.The titanium compound solution may be prepared by dissolving at least one titanium compound of titanium oxychloride (TiOCl 2 ) and titanium tetrachloride (TiCl 4 ) in water. The concentration of the titanium compound solution may be 0.2 ~ 2.0 mol / L. When the concentration of the titanium compound solution is within the above range, the productivity of BT relative to the volume of the titanium compound solution is high, and the titanium compound does not precipitate.
상기 옥살산 용액은 옥살산(H2C2O4)을 물에 용해시켜 제조한 것일 수 있다. 이때, 상기 옥살산 용액은 상기 바륨 화합물 용액이나 상기 티탄 화합물 용액 보다 많은 양이 사용될 수 있다. 구체적으로, 상기 옥살산 용액의 농도범위는 0.2~5.0 mol/L일 수 있다. 상기 옥살산 용액의 농도가 상기 범위이내이면, 상기 옥살산 용액의 부피 대비 BT의 생산성이 높고, 옥살산이 물에 완전히 용해될 수 있다.The oxalic acid solution may be prepared by dissolving oxalic acid (H 2 C 2 O 4 ) in water. In this case, the oxalic acid solution may be used in an amount larger than that of the barium compound solution or the titanium compound solution. Specifically, the concentration range of the oxalic acid solution may be 0.2 ~ 5.0 mol / L. When the concentration of the oxalic acid solution is within the above range, the productivity of BT relative to the volume of the oxalic acid solution is high, and oxalic acid may be completely dissolved in water.
상기 BTO 합성단계는 20~100℃, 예를 들어, 50~90℃의 합성온도에서 수행될 수 있다. 상기 BTO 합성단계에서 상기 합성온도가 상기 범위이내이면, BTO의 생산성이 높고 합성된 BTO가 재분해되는 것을 방지할 수 있다.The BTO synthesis step may be carried out at a synthesis temperature of 20 ~ 100 ℃, for example, 50 ~ 90 ℃. When the synthesis temperature is within the range in the BTO synthesis step, the productivity of the BTO is high and the synthesized BTO can be prevented from being re-decomposed.
상기 BTO 합성단계에서 상기 바륨 화합물 용액 및 상기 티탄 화합물 용액은 혼합 용액의 형태로 또는 각각 별도로 상기 옥살산 용액과 동시에 또는 순차적으로 접촉할 수 있다. 상기 접촉은 노즐 분사에 의해 진행될 수 있으며, 상기 접촉이 이루어지는 시간 (즉, 접촉 시간)은 1~3시간일 수 있다. 이러한 접촉 시간은 노즐의 분사속도를 조절함으로써 달성될 수 있다. 분사노즐은 유체의 흐름에 따라 일류체 또는 이류체 노즐을 사용할 수 있으며, 일류체 노즐을 사용하는 것이 편리성 면에서나 균일한 침전물을 획득하는데 있어서 더욱 유리할 수 있다. 일류체 노즐로는 풀콘(full cone), 할로우 콘(hollow cone), 또는 플랫(flat) 등이 사용될 수 있다. 예를 들어, 바륨 화합물 용액으로서 염화바륨 수용액 및 티탄 화합물 용액으로서 옥시염화티탄 수용액을 옥살산 수용액과 접촉시켜 BTO[BaTiO(C2O4)2·4H2O]를 생성하는 과정은 하기 반응식 1과 같이 표시될 수 있다.In the BTO synthesis step, the barium compound solution and the titanium compound solution may be simultaneously or sequentially contacted with the oxalic acid solution in the form of a mixed solution or separately. The contact may be performed by nozzle spraying, and the contact time may be 1 to 3 hours. This contact time can be achieved by adjusting the injection speed of the nozzle. The injection nozzle may use a hydraulic or two-fluid nozzle depending on the flow of the fluid, and the use of the hydraulic nozzle may be more advantageous in terms of convenience or in obtaining a uniform precipitate. As the hydraulic nozzle, a full cone, a hollow cone, a flat, or the like may be used. For example, a process of producing BTO [BaTiO (C 2 O 4 ) 2 .4H 2 O] by contacting an aqueous solution of barium chloride as a barium compound solution and an aqueous solution of titanium oxychloride as a titanium compound solution with an oxalic acid solution is shown in Scheme 1 below. Can be displayed as:
[반응식 1]Scheme 1
BaCl2·2H2O + TiOCl2· + 2H2C2O4·2H2O → BaTiO(C2O4)2·4H2O + 4HCl BaCl 2 · 2H 2 O + TiOCl 2 · + 2H 2 C 2 O 4 · 2H 2 O → BaTiO (C 2 O 4) 2 · 4H 2 O + 4HCl
다음에, 상기 합성된 BTO를 숙성하고(BTO 숙성단계), 여과한 다음(BTO 여과단계), 물로 세정할 수 있다(BTO 세정단계). 상기 BTO 숙성단계는 0.5~2시간 동안 진행하는 것이 생산성 측면에서 유리할 수 있다. 여기서, 여과란, 구체적으로 원심분리기 또는 필터 프레스(filter press) 등을 이용하여 BTO 함유 BTO 슬러리로부터 고상의 BTO만을 분리해내는 공정을 말한다. 이후, 세정액의 pH가 중성이 될 때까지 과량의 물로 상기 여과된 BTO를 세정할 수 있다.Next, the synthesized BTO may be aged (BTO ripening step), filtered (BTO filtration step), and then washed with water (BTO washing step). The BTO ripening step may be advantageous in terms of productivity to proceed for 0.5 to 2 hours. Here, filtration means the process of separating only solid-phase BTO from the BTO containing BTO slurry using a centrifuge, a filter press, etc. specifically. Thereafter, the filtered BTO may be washed with excess water until the pH of the washing liquid becomes neutral.
다음에, 선택적으로, 상기 세정된 BTO를 80~150℃에서 8~12시간 동안 건조할 수 있다.Next, optionally, the washed BTO may be dried at 80 to 150 ° C. for 8 to 12 hours.
이후, 상기와 같은 과정을 거쳐 얻어진 BTO를 습식분쇄한다(BTO 습식분쇄단계). 여기서, 습식분쇄란 소정의 매질과 함께 BTO를 비즈밀(beads mill), 볼밀(ball mill) 및 어트리션 밀(attrition mill) 등과 같은 습식분쇄기에 투입하여 분쇄하는 것을 말한다. 여기서, 매질이란 알코올과 같은 유기매질이나 탈이온수(deionized water)와 같은 물을 의미하는 것으로, 유기매질을 사용하게 되면 분쇄효율이나 입도관리 측면에서는 유리하지만 비용이 증가하는 단점이 있고, 물을 사용하게 되면 공정이 단순해져서 비용을 절감할 수 있는 잇점이 있다. 상기 매질로서 물을 사용하는 경우, 이의 사용량은 BTO 1중량부에 대하여 1~10중량부일 수 있다. 상기 물의 사용량이 상기 범위이내이면, 점도가 적당하여 분쇄가 용이하고, 물의 부피 대비 BTO의 생산성이 높다. 분쇄시간은 분쇄설비에 따라 분쇄력의 차이가 발생하여 적절히 제어될 필요가 있으며, 비즈밀을 사용하는 경우 10~300분일 수 있다. 이와 같이 분쇄시간을 조절함으로써 최종 제품인 BT 분말의 입도를 적절하게 조절할 수 있다. 이러한 습식분쇄 과정 중에 암모니아와 같은 질소함유 첨가제를 더 첨가할 수 있는데, 이로써 분쇄 전후의 혼합물의 산성화, 분쇄 후의 BTO 슬러리의 고점도화, 합성된 BTO 내의 염소이온 존재로 인한 분말의 유전특성 감소 문제를 부분적으로 또는 완전히 해결할 수 있다. Then, wet grinding the BTO obtained through the above process (BTO wet grinding step). Here, the wet grinding refers to grinding the BTO with a predetermined medium in a wet grinding machine such as a beads mill, a ball mill, an attrition mill, and the like. Here, the medium means an organic medium such as alcohol or water such as deionized water, and the use of an organic medium is advantageous in terms of crushing efficiency or particle size, but has a disadvantage of increasing cost. This simplifies the process and has the advantage of reducing costs. When water is used as the medium, its amount may be 1 to 10 parts by weight based on 1 part by weight of BTO. When the amount of water used is within the above range, the viscosity is moderate, so that grinding is easy, and the productivity of BTO is high relative to the volume of water. The grinding time needs to be appropriately controlled due to a difference in grinding force depending on the grinding equipment, and may be 10 to 300 minutes when a bead mill is used. By controlling the grinding time as described above, the particle size of the final product BT powder can be properly adjusted. Nitrogen-containing additives such as ammonia may be added during this wet grinding process, thereby reducing acidity of the powder due to acidification of the mixture before and after grinding, high viscosity of the BTO slurry after grinding, and the presence of chlorine ions in the synthesized BTO. It can be solved partially or completely.
다음에, 상기 습식분쇄된 BTO를 400℃ 이하의 온도에서 건조하여 사용된 매질을 제거한다(BTO 건조단계). 결과로서, 건조된 BTO 분말을 얻는다. 이 경우, 사용된 매질을 증발시켜 제거하기 위해, 상기 건조온도가 상기 매질의 끓는점 이상이 되어야 함은 당연하다.Next, the wet milled BTO is dried at a temperature below 400 ° C. to remove the used medium (BTO drying step). As a result, dried BTO powder is obtained. In this case, it is natural that the drying temperature should be above the boiling point of the medium in order to evaporate and remove the used medium.
이후, 상기 건조된 BTO를 건식분쇄한다(BTO 건식분쇄단계). 결과로서, 건식분쇄된 BTO 분말을 얻는다. Thereafter, the dried BTO is dry milled (BTO dry milling step). As a result, a dry pulverized BTO powder is obtained.
상기 BTO 건식분쇄단계는 상기 건식분쇄된 BTO의 부피 밀도(bulk density)가 0.2g/cm3 이상 0.50g/cm3 이하로 될 때까지 실시된다. 이에 따라, 상기 건식분쇄된 BTO 분말을 열처리하여 제조한 티탄산바륨 분말 중 응집체의 비율 및 네킹(necking) 비율이 감소할 수 있으며, BTO의 열처리시(즉, BT 합성단계시), BTO가 분해되어 생성되는 가스(CO, CO2, H2O 등)가 효율적으로 제거되어 BT에 형성되는 결함이 최소화되고, 이에 따라 결정성 높은 BT가 얻어질 수 있다. 본 명세서에서, 「네킹」이란 2 이상의 입자가 서로 결합될 경우 그 경계에 잘록한 부분이 생기는 것을 의미한다.The BTO dry grinding step is performed until the bulk density of the dry milled BTO is 0.2 g / cm 3 or more and 0.50 g / cm 3 or less. Accordingly, the ratio of the aggregates and the necking ratio in the barium titanate powder prepared by heat-treating the dry pulverized BTO powder may be reduced, and during the heat treatment of the BTO (that is, during the BT synthesis step), the BTO is decomposed. The generated gases (CO, CO 2 , H 2 O, etc.) are efficiently removed to minimize defects formed in the BT, so that a highly crystalline BT can be obtained. In the present specification, "necking" means that when the two or more particles are bonded to each other, a constricted portion is formed at the boundary thereof.
상기 건식분쇄된 BTO는 2.5㎛ 이하의 입경(PSA D50) 및 8.0㎛ 이하의 입경(PSA D90)을 가질 수 있다. 본 명세서에서, 입경(PSA D10, PSA D50 및 PSA D90)은 입도분석기(Malvern社 Mastersizer 2000)로 측정된 것이다.The dry milled BTO may have a particle size of 2.5 μm or less (PSA D50) and a particle size of 8.0 μm or less (PSA D90). In this specification, particle diameters (PSA D10, PSA D50 and PSA D90) are measured by a particle size analyzer (Malvern's Mastersizer 2000).
이하, 도 1a 을 참조하여, 상기 BTO 건식분쇄단계의 작용 및 효과를 상세히 설명한다.Hereinafter, with reference to Figure 1a, the operation and effects of the BTO dry grinding step will be described in detail.
도 1a를 참조하면, 상기 BTO 건식분쇄단계에 의해, 상기 건식분쇄된 BTO 분말의 부피 밀도가 0.50g/cm3 이하로 감소함으로써, 상기 건식분쇄된 BTO 분말은 응집체의 형성 비율이 낮아져 각 입자들이 서로 분리된 상태로 존재하는 비율이 증가한다. 반면에, 상기 건식분쇄된 BTO 분말의 부피 밀도가 0.2g/cm3 미만으로 감소하게 되면, 미립의 BTO가 서로 분리되지 않고 재응집된 상태로 존재하여 열처리시 BT분말에는 응집체 형성의 결과로 인한 공극이 존재하며, 미립으로 존재하는 BTO 분말은 열처리시 느린 BTO 입자간 확산 속도로 인해 입성장이 느린 문제점이 있다. 이에 따라, 상기 건식분쇄된 BTO 분말, 즉 부피밀도가 0.2g/cm3 이상 0.5g/cm3 이하인 BTO 분말을 열처리할 경우, 합성된 BT 입자들이 서로 분리된 상태로 존재하는 비율이 높은 BT 분말을 형성하게 된다. 이후, 상기 BT 분말을 MLCC에 적용한다. 즉, 상기 BT 분말을 두 전극층(10) 사이에 배치하여 유전층(20)을 형성함으로써 MLCC를 제조한다. 이때, 상기 유전층(20)은 서로 응집되지 않고 규칙적으로 배열된 BT 입자들을 높은 비율로 포함한다. 이어서, 상기 MLCC를 소결한다. 이때, 상기 유전층(20)의 BT 입자들이 결정화되어 공극이 없는 결정구조를 형성한다. 이와 같이, 도 1a는 상기 BTO 건식분쇄단계가 결정화도가 높은 BT를 형성하게 하는 작용 및 효과를 가짐을 예시한다.Referring to FIG. 1A, by the BTO dry grinding step, the bulk density of the dry milled BTO powder is reduced to 0.50 g / cm 3 or less, so that the dry milled BTO powder has a low formation rate of aggregates, thereby allowing each particle to be formed. The ratio of being separated from each other increases. On the other hand, if the bulk density of the dry pulverized BTO powder is reduced to less than 0.2g / cm 3 , the fine BTO is present in a reaggregated state without being separated from each other due to the result of the formation of aggregates in the BT powder during heat treatment Pore is present, the BTO powder is present as a particulate has a problem that the grain growth is slow due to the slow diffusion rate between BTO particles during heat treatment. Accordingly, when the dry pulverized BTO powder, that is, BTO powder having a bulk density of 0.2 g / cm 3 or more and 0.5 g / cm 3 or less, is heat treated, BT powder having a high ratio of the synthesized BT particles in a state in which they are separated from each other Will form. The BT powder is then applied to MLCC. That is, the MLCC is manufactured by disposing the BT powder between the two electrode layers 10 to form the dielectric layer 20. In this case, the dielectric layer 20 includes BT particles which are regularly arranged without aggregation with each other at a high ratio. Subsequently, the MLCC is sintered. In this case, the BT particles of the dielectric layer 20 are crystallized to form a crystal structure without voids. As such, Figure 1a illustrates that the BTO dry grinding step has the action and effect of forming a high crystallinity BT.
이하, 도 1b를 참조하여, 종래의 바륨티타닐옥살레이트(BTO)의 제조방법에서와 같이, BTO 건식분쇄단계가 없거나 적절하지 않을 경우 발생하는 문제점을 상세히 설명한다.Hereinafter, with reference to Figure 1b, as in the conventional method for producing barium titanyl oxalate (BTO), the problem that occurs when the BTO dry grinding step is missing or not in detail will be described in detail.
도 1b를 참조하면, 상기 BTO 건식분쇄단계가 없거나 적절하지 않을 경우, 상기 건식분쇄된 BTO 분말은 BTO 입자들 중의 적어도 일부가 응집체를 형성한 상태로 존재한다. 이에 따라, 상기 건식분쇄된 BTO 분말을 열처리할 경우, 합성된 BT 입자들 중의 적어도 일부가 응집체를 형성한 상태로 존재하는 BT 분말을 형성하게 된다. 또한, 상기 BT 분말에는 응집체 형성의 결과물인 공극이 존재하게 된다. 이후, 상기 BT 분말을 MLCC에 적용한다. 즉, 상기 BT 분말을 두 전극층(10) 사이에 배치하여 유전층(20')을 형성함으로써 MLCC를 제조한다. 이때, 상기 유전층(20')은 서로 응집되어 불규칙적으로 배열된 BT 입자들을 높은 비율로 포함한다. 이어서, 상기 MLCC를 소결한다. 이때, 상기 유전층(20')의 BT 입자들이 결정화되어 공극을 포함하는 결정구조를 형성한다. 이와 같이, 도 1b는 상기 BTO 건식분쇄단계가 없을 경우 결정화도가 낮은 BT가 형성되게 되는 문제점을 예시한다.Referring to FIG. 1B, if the BTO dry grinding step is absent or inadequate, the dry milled BTO powder is present with at least some of the BTO particles forming aggregates. Accordingly, when the dry pulverized BTO powder is heat-treated, at least some of the synthesized BT particles form BT powder in a state in which aggregates are formed. In addition, the BT powder has voids that are a result of the formation of aggregates. The BT powder is then applied to MLCC. That is, the MLCC is manufactured by disposing the BT powder between two electrode layers 10 to form a dielectric layer 20 '. In this case, the dielectric layer 20 ′ contains a high proportion of BT particles aggregated and irregularly arranged together. Subsequently, the MLCC is sintered. In this case, the BT particles of the dielectric layer 20 ′ are crystallized to form a crystal structure including pores. As such, FIG. 1B illustrates a problem in which the low crystallinity BT is formed when the BTO dry grinding step is not present.
상기 BTO 건식분쇄단계는 해머밀(hammer mill), 기류분급분쇄기(ACM: air classifying mill) 및 제트밀(jet mill)로 이루어진 군으로부터 선택된 적어도 1종의 분쇄기를 사용하여 실시될 수 있다. 상기 해머밀 및 기류분급분쇄기의 로터 회전속도, 및 상기 제트밀의 공기압은 상기 건식분쇄된 BTO의 부피 밀도가 0.2g/cm3 이상 0.50g/cm3 이하로 되도록 적당히 조절될 수 있다.The BTO dry grinding step may be performed using at least one grinder selected from the group consisting of a hammer mill, an air classifying mill (ACM) and a jet mill. The rotor rotational speed of the hammer mill and the air classifier, and the air pressure of the jet mill can be appropriately adjusted so that the bulk density of the dry milled BTO is 0.2g / cm 3 or more and 0.50g / cm 3 or less.
이어서, 상기 BTO 분말을 가열로에 충전시킨 다음, 800~1000℃에서 열처리하여 티탄산바륨[BaTiO3](이하, 간단히 BT라고 함)을 합성한다(BT 합성단계). 상기 BT 합성단계에서 상기 열처리온도가 상기 범위이내이면, 목표로 하는 입경(PSA D50)(즉, 0.08~0.5㎛)의 티탄산바륨을 얻을 수 있다. 상기 BT 합성단계에서는 수분 및/또는 탄소를 포함하는 불순물(CO, CO2, H2O 등)이 제거될 수 있다. 상기 BTO 건조단계의 건조온도에서부터 상기 BT 합성단계의 상기 열처리온도로의 승온속도는 0.5~10℃/min, 예를 들어 1~5℃/min일 수 있다. 상기 승온속도가 상기 범위이내이면, BT의 생산성이 높고, 온도분포가 균일해져 BT 분말의 입도가 균일해진다. 이와 같이 상기 BT 합성단계를 수행함으로써, BTO 결정의 내부에 결정수로 존재하는 수분과 과량의 탄산가스를 제거하여 하기 반응식 2 내지 4와 같은 과정을 거쳐 수십 nm 내지 수백 nm 크기의 BT 분말을 얻을 수 있다.Subsequently, the BTO powder is charged into a heating furnace, followed by heat treatment at 800 to 1000 ° C. to synthesize barium titanate [BaTiO 3 ] (hereinafter, simply referred to as BT). In the BT synthesis step, when the heat treatment temperature is within the range, barium titanate having a target particle size (PSA D50) (that is, 0.08 to 0.5 μm) may be obtained. In the BT synthesis step, impurities (CO, CO 2 , H 2 O, etc.) including water and / or carbon may be removed. The temperature increase rate from the drying temperature of the BTO drying step to the heat treatment temperature of the BT synthesis step may be 0.5 ~ 10 ℃ / min, for example 1 ~ 5 ℃ / min. If the temperature increase rate is within the above range, the productivity of BT is high, the temperature distribution is uniform, and the particle size of the BT powder is uniform. By performing the BT synthesis step as described above, BT powder of several tens nm to hundreds of nm is obtained by removing water and excess carbon dioxide gas which are present as crystal water inside the BTO crystal through the process as in Schemes 2 to 4 below. Can be.
[반응식 2]Scheme 2
BaTiO(C2O4)2·4H2O → BaTiO(C2O4)2 + 4H2OBaTiO (C 2 O 4 ) 2 4H 2 O → BaTiO (C 2 O 4 ) 2 + 4H 2 O
[반응식 3]Scheme 3
BaTiO(C2O4)2 + 1/2 O2 → BaCO3 + TiO2 + 2CO2 BaTiO (C 2 O 4 ) 2 + 1/2 O 2 → BaCO 3 + TiO 2 + 2CO 2
[반응식 4]Scheme 4
BaCO3 + TiO2 → BaTiO3 BaCO 3 + TiO 2 → BaTiO 3
상기 건조된 BTO 분말의 열처리를 위해 가열로로서 Sagger 또는 Tray가 사용될 수 있다. 여기서, Sagger란 내화토(耐火土) 용기를 의미한다. 상기 Sagger는, 예를 들어, 정사각형 형태의 밑면을 갖는 육면체 형상의 용기일 수 있다. Sagger or Tray may be used as a heating furnace for heat treatment of the dried BTO powder. Here, Sagger means a refractory soil container. The sagger may be, for example, a cube-shaped container having a bottom surface of a square shape.
이후, 상기 BT 합성단계를 통해 생성된 BT를 분쇄하여 BT 분말을 얻는다(BT 분쇄단계). 그러나, 이러한 BT 분쇄단계는 생략될 수도 있다. 상기 BT 분쇄단계는, 소정의 매질과 함께 비즈밀(beads mill), 어트리션밀(attrition mill), 또는 볼밀(ball mill)과 같은 분쇄기를 사용하는 습식분쇄에 의해 수행될 수도 있고, 제트밀(jet mill) 또는 디스크밀(disk mill)과 같이 매질을 사용하지 않은 상태에서 원료간의 충돌이나 분쇄기와의 마찰력을 이용하는 건식분쇄에 의해 수행될 수도 있다. 상기 분쇄단계는 티탄산바륨의 입자간 응집을 해소하기 위한 것으로, 습식분쇄를 행한 후에는 건조과정이 추가로 필요하지만 건조를 위해 특별히 한정된 설비를 사용해야 하는 것은 아니다. 상기 BT 분쇄단계에서 분쇄효율이 지나치게 높은 설비를 사용할 경우, 입자의 파괴가 유발되어 미분이 다량으로 발생하게 되고, 이로 인해 오히려 입도분포와 결정성이 저하될 가능성이 있으므로 가능한 한 분쇄 강도를 낮춰서 입자 자체의 파괴없이 입자간의 결합(necking)만을 끊어줄 수 있다. Thereafter, the BT produced through the BT synthesis step is pulverized to obtain BT powder (BT crushing step). However, this BT grinding step may be omitted. The BT grinding step may be performed by wet grinding using a grinder such as a beads mill, an attention mill, or a ball mill with a predetermined medium, or a jet mill ( It may also be carried out by dry grinding using friction between the raw materials or friction with the pulverizer without using a medium such as a jet mill or a disk mill. The pulverization step is for resolving the agglomeration of particles of barium titanate. After the wet pulverization, a drying step is additionally required, but it is not necessary to use a particularly limited facility for drying. In the BT grinding step, when the equipment having a high grinding efficiency is used, particle breakage is caused, resulting in a large amount of fine powder. Accordingly, particle size distribution and crystallinity may be lowered, thereby lowering the grinding strength as much as possible. It can only break the necking of particles without breaking itself.
본 발명의 다른 측면은 상기 바륨티타닐옥살레이트의 제조방법을 포함하는 상기 티탄산바륨의 제조방법에 의해 제조된 티탄산바륨을 제공한다.Another aspect of the present invention provides a barium titanate prepared by the method for producing barium titanate including the method for producing barium titanyl oxalate.
상기 티탄산바륨으로 이루어진 티탄산바륨 분말은 10중량% 이하의 응집체를 포함할 수 있다. 본 명세서에서, 「응집체」란 소정량(예를 들어, 5g)의 BT 분말을 알코올(예를 들어, 에탄올 150ml)에 분산시켜 BT 분산액을 제조한 후, 상기 BT 분산액을 정량펌프를 이용하여 14㎛ 메쉬 크기의 필터에 주입하여 여과한 경우, 상기 필터를 통과하지 못하고 남아있는 물질을 의미한다.The barium titanate powder made of barium titanate may include an aggregate of 10 wt% or less. In the present specification, "aggregate" means a predetermined amount (for example, 5g) of BT powder in alcohol (for example, 150ml of ethanol) to prepare a BT dispersion, and then, the BT dispersion using a metering pump 14 When the filter is injected into a filter having a μm mesh size, it means a substance that cannot pass through the filter.
이하, 실시예를 들어 본 발명을 더욱 상세히 설명하지만, 본 발명이 이에 의해 제한되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
실시예Example
실시예 1~5 및 비교예 1~4Examples 1-5 and Comparative Examples 1-4
(BTO 합성 및 숙성)(BTO Synthesis and Aging)
1mol/L 농도의 염화바륨　수용액 1320L와 1mol/L 농도의 사염화티탄　수용액 1200L를 4M3　글래스-라인(glass-lined) 반응조에서 잘 섞어서 혼합 수용액을 만들었다. 이후, 상기 혼합 수용액을 6M3　반응기에 충진된, 미리 만들어둔 1mol/L 농도의 옥살산 수용액 2520L에 풀콘(full cone) 타입의 노즐을 이용하여 2.5L/min의 속도로 분사하였다. 노즐 분사시 상기 혼합 수용액의 공급을 위해 다이아프램 펌프를 사용하였다. 이때, 옥살산 용액을 교반기로 교반하면서 분사하였으며, 교반기의 교반속도는 150rpm으로 유지하였고, 옥살산 용액의 온도는 70℃로 유지하였다.1320L of a 1 mol / L barium chloride solution and 1200L of a 1 mol / L titanium tetrachloride solution were mixed well in a 4M 3 glass-lined reactor to form a mixed aqueous solution. Thereafter, the mixed aqueous solution was sprayed at a rate of 2.5 L / min using a full cone type nozzle to 2520 L of oxalic acid aqueous solution of 1 mol / L concentration, which was filled in a 6M 3 reactor. A diaphragm pump was used to supply the mixed aqueous solution during nozzle spraying. At this time, the oxalic acid solution was sprayed while stirring with a stirrer, the stirring speed of the stirrer was maintained at 150rpm, the temperature of the oxalic acid solution was maintained at 70 ℃.
2시간 동안 상기 혼합 수용액을 적가후 1시간 동안 반응온도를 유지한 다음, 교반을 유지한 채로 공냉시켜 1시간 동안 숙성시켰다. 결과로서, BTO를 함유하는 BTO 슬러리를 얻었다. After the dropwise addition of the mixed aqueous solution for 2 hours, the reaction temperature was maintained for 1 hour, and then air-cooled with stirring to mature for 1 hour. As a result, a BTO slurry containing BTO was obtained.
(합성된 BTO 슬러리의 여과 및 세정)(Filtration and washing of the synthesized BTO slurry)
상기에서 제조된 BTO 슬러리를 원심분리기로 여과하고, 과량의 물로 세정액의 pH가 3 이상이 되도록 세정하여 세정된 BTO를 얻었다.The BTO slurry prepared above was filtered with a centrifugal separator, and washed with excess water so that the pH of the washing liquid was 3 or more to obtain a washed BTO.
(세정된 BTO의 습식분쇄 및 건조)(Wet grinding and drying of cleaned BTO)
상기 BTO 50kg, 탈이온수 250kg 및 29부피% 암모니아수 0.5kg(BTO 100몰부 대비 8.4 몰부)을 혼합조에 투입하고 교반하여 슬러리를 생성하였다. 이때, 슬러리의 pH는 4.5이었다. 이후, 20L의 수평식 비즈밀(매질: 탈이온수)로 최대 입경이 5㎛ 이하가 되도록 상기 BTO를 습식분쇄하였다. 분쇄 후, 슬러리의 pH는 5.1, 점도는 1800cP이었다. 이렇게 얻어진 BTO 슬러리를 오븐안에서 200℃의 온도로 12시간 동안 건조하여 BTO 분말을 제조하였다.50 kg of the BTO, 250 kg of deionized water, and 0.5 kg of 29% by volume ammonia water (8. 4 mol parts relative to 100 mol parts of BTO) were added to a mixing tank and stirred to form a slurry. At this time, the pH of the slurry was 4.5. Thereafter, the BTO was wet milled with a 20 L horizontal beads mill (medium: deionized water) such that the maximum particle size was 5 µm or less. After grinding, the slurry had a pH of 5.1 and a viscosity of 1800 cP. Thus obtained BTO slurry was dried in an oven at a temperature of 200 ℃ for 12 hours to prepare a BTO powder.
(건조된 BTO의 건식분쇄)(Dry grinding of dried BTO)
상기 건조된 BTO를 해머밀(대가파우더시스템, DGHSM-2), 기류분급분쇄기 (베스트피티에스㈜, BCM-T1-00) 또는 제트밀(SEISHIN ENTERPRISE社, STJ-560)에 4kg/hr의 속도로 주입하여 건식분쇄하였다. 결과로서, 건식분쇄된 BTO를 얻었다. 상기 각 실시예 및 비교예에서 채택한 해머밀의 로터 회전속도, 기류분급분쇄기의 로터 회전속도, 및 제트밀의 공기압을 하기 표 1에 각각 나타내었다.The dried BTO was hammered at a speed of 4 kg / hr in a hammer mill (Daesung Powder System, DGHSM-2), air classifier (Best PTS Co., Ltd., BCM-T1-00) or jet mill (SEISHIN ENTERPRISE, STJ-560). It was injected into the dry grinding. As a result, dry milled BTO was obtained. The rotor rotation speed of the hammer mill, the rotor rotation speed of the air classifier, and the air pressure of the jet mill adopted in the above Examples and Comparative Examples are shown in Table 1, respectively.
표 1
건식분쇄장치 공정변수 회전 속도(rpm) 또는 공기압(MPa)
비교예 1 해머밀 로터의 회전속도 2000
비교예 2 4000
비교예 3 6000
비교예 4 ACM 로터의 회전속도 5000
실시예 1 8000
실시예 2 11000
실시예 3 제트밀 공기압 0.5
실시예 4 0.6
실시예 5 0.7
Table 1
Dry Grinding Device Process variables Rotational Speed (rpm) or Air Pressure (MPa)
Comparative Example 1 Hammer mill Rotor speed 2000
Comparative Example 2 4000
Comparative Example 3 6000
Comparative Example 4 ACM Rotor speed 5000
Example 1 8000
Example 2 11000
Example 3 Jet mill windage 0.5
Example 4 0.6
Example 5 0.7
(열처리, 습식분쇄 및 건조)(Heat treatment, wet grinding and drying)
상기 건식분쇄된 BTO 분말을 전기로(원준, RHK)에 투입한 후, 930℃에서 3시간 동안 열처리를 수행하였다. 결과로서, BT 분말을 얻었다. 이후, 상기 BT 분말을 20L의 수평식 비즈밀(매질: 탈이온수)로 주속 5m/s(즉, 1500rpm)으로 30분간 습식분쇄하였다. 상기 습식분쇄 후 형성된 BT 슬러리를 150℃ 오븐에서 24시간 동안 건조하였다. 결과로서, BT 분말을 얻었다.The dry pulverized BTO powder was put into an electric furnace (WonJun, RHK), and then heat-treated at 930 ° C. for 3 hours. As a result, BT powder was obtained. Thereafter, the BT powder was wet-pulverized for 30 minutes at a speed of 5 m / s (ie, 1500 rpm) with a 20 L horizontal beads mill (medium: deionized water). The BT slurry formed after the wet grinding was dried in an oven at 150 ° C. for 24 hours. As a result, BT powder was obtained.
평가예Evaluation example
평가예 1: 건식분쇄된 BTO의 부피 밀도 평가Evaluation Example 1 Evaluation of Bulk Density of Dry Milled BTO
상기 각 실시예 및 비교예에서 얻어진 건식분쇄된 BTO의 부피 밀도를 측정하여, 그 결과를 하기 표 2에 나타내었다. 구체적으로, ISO 23145-1 규격에 의거하여 상기 건식분쇄된 BTO(즉, BTO 분말)의 부피 밀도를 측정하였다.The bulk density of the dry milled BTO obtained in each of the above Examples and Comparative Examples was measured, and the results are shown in Table 2 below. Specifically, the bulk density of the dry milled BTO (ie, BTO powder) was measured according to the ISO 23145-1 standard.
평가예 2: BTO의 입경 측정Evaluation example 2 particle size measurement of BTO
상기 각 실시예 및 비교예에서 얻어진 건식분쇄된 BTO의 입경(PSA D10, PSA D50 및 PSA D90을 측정한 후, 그 결과를 하기 표 2에 나타내었다. 여기서, 상기 입경(PSA D10, PSA D50 및 PSA D90)은 입도분석기(Malvern社, Mastersizer2000)를 사용하여 측정하였다. After measuring the particle size (PSA D10, PSA D50 and PSA D90) of the dry ground BTO obtained in each of the above Examples and Comparative Examples, the results are shown in Table 2. Here, the particle diameters (PSA D10, PSA D50 and PSA D90) was measured using a particle size analyzer (Malvern, Mastersizer2000).
표 2
부피 밀도(g/cm3) 입경(㎛)
PSA D10 PSA D50 PSA D90
비교예 1 0.57 3.68 16.5 41.51
비교예 2 0.53 2.59 12.54 33.92
비교예 3 0.52 2.21 7.16 20.54
비교예 4 0.55 2.71 13.19 38.11
실시예 1 0.48 1.56 6.16 19.34
실시예 2 0.37 0.82 2.61 10.21
실시예 3 0.39 1.38 5.12 12.86
실시예 4 0.36 0.78 2.44 11.22
실시예 5 0.31 0.72 2.05 6.21
TABLE 2
Bulk density (g / cm 3 ) Particle size (㎛)
PSA D10 PSA D50 PSA D90
Comparative Example 1 0.57 3.68 16.5 41.51
Comparative Example 2 0.53 2.59 12.54 33.92
Comparative Example 3 0.52 2.21 7.16 20.54
Comparative Example 4 0.55 2.71 13.19 38.11
Example 1 0.48 1.56 6.16 19.34
Example 2 0.37 0.82 2.61 10.21
Example 3 0.39 1.38 5.12 12.86
Example 4 0.36 0.78 2.44 11.22
Example 5 0.31 0.72 2.05 6.21
상기 표 2를 참조하면, 실시예 1~5에서 제조된 BTO는 비교예 1~4에서 제조된 BTO에 비해 입경(PSA D10, PSA D50 및 PSA D90)이 작은 것으로 나타났다.Referring to Table 2, the BTO prepared in Examples 1 to 5 was found to have a smaller particle size (PSA D10, PSA D50 and PSA D90) than the BTO prepared in Comparative Examples 1 to 4.
평가예 2: 합성된 BT의 결정화도(k-factor 및 c/a) 평가Evaluation Example 2 Evaluation of Crystallinity (k-factor and c / a) of Synthesized BT
상기 각 실시예 및 비교예에서 합성된 BT의 결정화도(k-factor 및 c/a)를 XRD(Rigaku사의 D/Max 2000 series)로 측정하여, 그 결과를 하기 표 3에 나타내었다. 구체적으로, 40kV, 200mA에서 2sec/step의 속도와 0.02의 step size의 XRD 분석조건으로, 2θ = 44.5~46도(°)의 범위에 대하여 분석하였다. 이후, 도 5에 도시된 것과 같은 XRD 스펙트럼에서, 입방정상의 분율(Ic)에 대한 정방정상의 분율(It)의 비(It/Ic)로서 BT 입자의 k-factor를 계산하였다. 또한, 결정 격자의 a축과 c축의 d-spacing 값을 구한 후 이들의 비로써 BT 입자의 c/a를 계산하였다. 그 결과를 하기 표 3에 나타내었다. 도 5에는, 실시예 2, 실시예 5 및 비교예 3에서 제조된 BT의 XRD 스펙트럼을 나타내었다.Crystallization degree (k-factor and c / a) of BT synthesized in each of Examples and Comparative Examples was measured by XRD (D / Max 2000 series of Rigaku), and the results are shown in Table 3 below. Specifically, 2θ = 44.5 ~ 46 degrees (°) was analyzed by XRD analysis conditions of the speed of 2sec / step and step size of 0.02 at 40kV, 200mA. Then, in the XRD spectrum as shown in Figure 5, the k-factor of the BT particles was calculated as the ratio (I t / I c ) of the fraction of the tetragonal phase (I t ) to the fraction of the cubic phase (I c ). In addition, after calculating the d-spacing values of the a-axis and the c-axis of the crystal lattice, c / a of the BT particles was calculated from these ratios. The results are shown in Table 3 below. In FIG. 5, XRD spectra of BT prepared in Example 2, Example 5, and Comparative Example 3 are shown.
평가예 3: 합성된 BT의 입경(SEM D50) 측정Evaluation Example 3: Measurement of Particle Size (SEM D50) of Synthesized BT
상기 각 실시예 및 비교예에서 얻어진 건조 완료 후의 BT의 입경(SEM D50)을 측정한 다음, 그 결과를 하기 표 3에 나타내었다. 여기서, 상기 입경(SEM D50)은 주사전자현미경(SEM, Jeol사의 JSM-7400F)을 이용하여 이미지 촬영후 이미지 분석 프로그램(Mediacybernetics社의 이미지프로 플러스 ver 4.5)을 이용하여 티탄산바륨 입자의 장축과 단축의 평균으로 평균입경을 계산한 후 이 평균입경을 기초로 하여 얻어졌으며, 측정한 티탄산바륨 입자의 개수는 500개 이상이었다.After measuring the particle size (SEM D50) of the BT after the completion of drying obtained in each of the above Examples and Comparative Examples, the results are shown in Table 3 below. Here, the particle diameter (SEM D50) is the long axis and shortening of the barium titanate particles using an image analysis program (ImagePro Plus ver 4.5 of Mediacybernetics, Inc.) after taking an image using a scanning electron microscope (SEM, Jeol JSM-7400F) The average particle diameter was calculated based on the average particle diameter, and was obtained based on the average particle diameter. The number of measured barium titanate particles was 500 or more.
평가예 4: 합성된 BT의 비표면적 평가Evaluation Example 4: Evaluation of Specific Surface Area of Synthesized BT
상기 각 실시예 및 비교예에서 합성된 BT의 비표면적을 비표면적 측정기(Mountech사, Macsorb HM-1220)로 분석하여, 그 결과를 하기 표 3에 나타내었다.The specific surface area of the BT synthesized in each of the above Examples and Comparative Examples was analyzed by a specific surface area meter (Mountech, Macsorb HM-1220), and the results are shown in Table 3 below.
평가예 5: 합성된 BT 분말 중의 응집체의 함량 평가Evaluation Example 5 Evaluation of Content of Aggregates in Synthesized BT Powder
상기 각 실시예 및 비교예에서 합성된 BT 분말 중의 응집체의 함량을 분석하여, 그 결과를 하기 표 3에 나타내었다. 구체적으로, 상기 각 실시예 및 비교예에서 합성된 BT 분말 5g을 에탄올 150ml에 분산시켜 BT 분산액을 제조한 후, 상기 BT 분산액을 정량펌프(Masterflex, 7528-10S)를 이용하여 14㎛ 메쉬 크기의 필터(일동금망, stainless steel mesh)에 주입하여 여과하였다. 이어서, 상기 필터를 통과하지 못하고 남아있는 물질의 함량(WR)을 'g' 단위로 측정하였다. 이후, 하기 수학식 1에 따라 응집체의 함량을 계산하였다.The content of aggregates in the BT powder synthesized in each of Examples and Comparative Examples was analyzed, and the results are shown in Table 3 below. Specifically, after dispersing the BT powder synthesized in each of the above Examples and Comparative Examples in 150ml of ethanol to prepare a BT dispersion, the BT dispersion using a metering pump (Masterflex, 7528-10S) of 14㎛ mesh size The filter was injected into a stainless steel mesh and filtered. Subsequently, the content (W R ) of the substance remaining without passing through the filter was measured in units of 'g'. Then, the content of the aggregate was calculated according to the following equation (1).
[수학식 1][Equation 1]
응집체의 함량(wt%) = WR/5 * 100Aggregate content (wt%) = W R / 5 * 100
표 3
결정화도 SEM D50(nm) 비표면적(m2/g) 응집체의 함량(wt%)
k-factor c/a
비교예 1 3.90 1.0097 211 2.89 18.19
비교예 2 4.74 1.0099 205 3.15 13.88
비교예 3 5.18 1.0100 203 3.37 10.13
비교예 4 4.18 1.0097 208 3.00 14.95
실시예 1 5.62 1.0101 201 3.42 8.13
실시예 2 6.99 1.0105 194 3.75 5.41
실시예 3 5.84 1.0102 197 3.52 7.94
실시예 4 6.90 1.0104 195 3.73 5.91
실시예 5 7.84 1.0106 183 4.30 0.30
TABLE 3
Crystallinity SEM D50 (nm) Specific surface area (m 2 / g) Aggregate content (wt%)
k-factor c / a
Comparative Example 1 3.90 1.0097 211 2.89 18.19
Comparative Example 2 4.74 1.0099 205 3.15 13.88
Comparative Example 3 5.18 1.0100 203 3.37 10.13
Comparative Example 4 4.18 1.0097 208 3.00 14.95
Example 1 5.62 1.0101 201 3.42 8.13
Example 2 6.99 1.0105 194 3.75 5.41
Example 3 5.84 1.0102 197 3.52 7.94
Example 4 6.90 1.0104 195 3.73 5.91
Example 5 7.84 1.0106 183 4.30 0.30
상기 표 3을 참조하면, 실시예 1~5에서 제조된 BT는 비교예 1~4에서 제조된 BT에 비해 결정화도(k-factor 및 c/a)는 높고, 입경(SEM D50)은 작으며, 비표면적은 크고, 응집체의 함량은 매우 적은 것으로 나타났다.Referring to Table 3, the BT prepared in Examples 1 to 5 has a higher crystallinity (k-factor and c / a) and a smaller particle size (SEM D50) than the BT prepared in Comparative Examples 1 to 4, The specific surface area was large and the content of aggregate was found to be very small.
평가예 6: BTO 분말의 SEM 평가Evaluation Example 6: SEM Evaluation of BTO Powder
건식분쇄 전과 후의 BTO 분말의 SEM 사진을 촬영하여, 그 결과를 도 2에 나타내었다. 도 2에서, (a)는 상기 실시예 1~5 및 비교예 1~4에서 제조된 건식분쇄 전의 BTO 분말이고, (b)는 비교예 3에서 제조된 건식분쇄 후의 BTO 분말이고, (c)는 실시예 2에서 제조된 건식분쇄 후의 BTO 분말이고, (d)는 실시예 5에서 제조된 건식분쇄 후의 BTO 분말이다.SEM images of the BTO powder before and after the dry grinding were taken and the results are shown in FIG. 2. In Figure 2, (a) is the BTO powder before dry grinding prepared in Examples 1 to 5 and Comparative Examples 1 to 4, (b) is the BTO powder after dry grinding prepared in Comparative Example 3, (c) Is BTO powder after dry grinding prepared in Example 2, and (d) is BTO powder after dry grinding prepared in Example 5.
도 2를 참조하면, 실시예 2 및 5에서 제조된 건식분쇄 후의 BTO 분말((c) 및 (d))은 건식 분쇄 전의 BTO 분말((a)) 및 비교예 3에서 제조된 건식분쇄 후의 BTO 분말((b))에 비해 응집체의 함량이 현저하게 적은 것으로 나타났다. 2, the BTO powders ((c) and (d) after dry grinding prepared in Examples 2 and 5 are BTO powders ((a)) before dry grinding and BTO after dry grinding prepared in Comparative Example 3 The content of aggregates was found to be significantly lower than the powder ((b)).
평가예 7: BT 응집체의 사진 평가Evaluation Example 7 Photo Evaluation of BT Aggregates
평가예 5에 따라 BT 분산액을 제조 및 여과한 후 필터를 통과하지 못하고 남아있는 응집체를 촬영하여, 그 결과를 도 3에 나타내었다. 도 3에서, (a)는 상기 실시예 1~5 및 비교예 1~4에서 제조된 건식분쇄 전의 BT 분말을 사용한 경우이고, (b)는 비교예 3에서 제조된 건식분쇄 후의 BT 분말을 사용한 경우이고, (c)는 실시예 2에서 제조된 건식분쇄 후의 BT 분말을 사용한 경우이고, (d)는 실시예 5에서 제조된 건식분쇄 후의 BT 분말을 사용한 경우이다.After the BT dispersion was prepared and filtered according to Evaluation Example 5, the aggregates remaining without passing through the filter were photographed, and the results are shown in FIG. 3. In Figure 3, (a) is the case of using the BT powder before the dry grinding prepared in Examples 1 to 5 and Comparative Examples 1 to 4, (b) using the BT powder after the dry grinding prepared in Comparative Example 3 In this case, (c) is the case of using the BT powder after dry grinding prepared in Example 2, (d) is a case of using the BT powder after dry grinding prepared in Example 5.
도 3을 참조하면, 실시예 2 및 5에서 제조된 건식분쇄 후의 BT 분말((c) 및 (d))은 건식 분쇄 전의 BT 분말((a)) 및 비교예 3에서 제조된 건식분쇄 후의 BT 분말((b))에 비해 응집체의 함량이 현저하게 적은 것으로 나타났다. Referring to FIG. 3, the BT powders ((c) and (d) after dry grinding prepared in Examples 2 and 5 are BT powders ((a)) before dry grinding and BT after dry grinding prepared in Comparative Example 3 The content of aggregates was found to be significantly lower than the powder ((b)).
평가예 8: BT 분말의 SEM 평가Evaluation Example 8: SEM Evaluation of BT Powder
건식분쇄 전과 후의 BTO 분말을 열처리하여 제조한 BT 분말의 SEM 사진을 촬영하여, 그 결과를 도 4에 나타내었다. 도 4에서, (a)는 상기 실시예 1~5 및 비교예 1~4에서 제조된 건식분쇄 전의 BTO 분말을 건식분쇄 없이 곧바로 열처리하여 제조한 BT 분말이고, (b)는 비교예 3에서 제조된 BT 분말이고, (c)는 실시예 2에서 제조된 BT 분말이고, (d)는 실시예 5에서 제조된 BT 분말이다.SEM pictures of the BT powder prepared by heat-treating the BTO powder before and after the dry grinding were taken, and the results are shown in FIG. 4. In Figure 4, (a) is a BT powder prepared by directly heat-treating the BTO powder before dry grinding prepared in Examples 1 to 5 and Comparative Examples 1 to 4 without dry grinding, (b) is prepared in Comparative Example 3 Is a BT powder prepared in Example 2, (c) is a BT powder prepared in Example 2, and (d) is a BT powder prepared in Example 5.
도 4를 참조하면, 실시예 2 및 5에서 제조된 BT 분말((c) 및 (d))은 건식 분쇄 전의 BTO 분말을 건식분쇄 없이 곧바로 열처리하여 제조한 BT 분말((a)) 및 비교예 3에서 제조된 BT 분말((b))과 비교할 경우, 입자크기는 서로 비슷하지만 응집체의 함량은 현저하게 적은 것으로 나타났다. Referring to FIG. 4, the BT powders ((c) and (d)) prepared in Examples 2 and 5 are BT powders ((a)) prepared by directly heat-treating the BTO powder before dry grinding and a comparative example. Compared with the BT powder prepared in (3) (b), the particle size was similar to each other, but the content of aggregates was found to be remarkably small.
본 발명은 도면 및 실시예를 참고로 설명되었으나 이는 예시적인 것에 불과하며, 본 기술 분야의 통상의 지식을 가진 자라면 이로부터 다양한 변형 및 균등한 다른 실시예가 가능하다는 점을 이해할 것이다. 따라서, 본 발명의 진정한 기술적 보호 범위는 첨부된 특허청구범위의 기술적 사상에 의하여 정해져야 할 것이다.Although the present invention has been described with reference to the drawings and embodiments, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (10)

  1. 바륨 화합물 용액, 티탄 화합물 용액 및 옥살산 용액을 제조하는 단계(원료 용액 제조단계); Preparing a barium compound solution, a titanium compound solution, and an oxalic acid solution (raw material solution preparing step);
    상기 바륨 화합물 용액과 상기 티탄 화합물 용액을 상기 옥살산 용액과 접촉시켜 바륨티타닐옥살레이트[BaTiO(C2O4)2·4H2O](이하, 간단히 BTO라고 함)를 합성하는 단계(BTO 합성단계); Contacting the barium compound solution and the titanium compound solution with the oxalic acid solution to synthesize barium titanyl oxalate [BaTiO (C 2 O 4 ) 2 .4H 2 O] (hereinafter simply referred to as BTO). step);
    상기 합성된 BTO를 습식분쇄하는 단계(BTO 습식분쇄단계);Wet grinding the synthesized BTO (BTO wet grinding step);
    상기 습식분쇄된 BTO를 건조하여 BTO 분말을 얻는 단계(BTO 건조단계); 및Drying the wet milled BTO to obtain a BTO powder (BTO drying step); And
    상기 건조된 BTO를 건식분쇄하는 단계(BTO 건식분쇄단계)를 포함하고,Dry grinding the dried BTO (BTO dry grinding step),
    상기 BTO 건식분쇄단계는 상기 건식분쇄된 BTO의 부피 밀도(bulk density)가 0.2g/cm3 이상 0.50g/cm3 이하로 될 때까지 실시되는 바륨티타닐옥살레이트의 제조방법.The BTO dry grinding step is a method for producing barium titanyl oxalate is carried out until the bulk density of the dry pulverized BTO is 0.2g / cm 3 or more and 0.50g / cm 3 or less.
  2. 제1항에 있어서,The method of claim 1,
    상기 바륨 화합물 용액은 염화바륨(BaCl2), 질산바륨(Ba(NO3)2) 및 과염소산바륨(Ba(ClO4)2)으로 이루어진 군으로부터 선택된 적어도 1종의 바륨 화합물을 물에 용해시켜 제조한 것이고, 상기 티탄 화합물 용액은 옥시염화티탄(TiOCl2) 및 사염화티탄(TiCl4) 중 적어도 1종의 티탄 화합물을 물에 용해시켜 제조한 것이고, 상기 옥살산 용액은 옥살산을 물에 용해시켜 제조한 것인 바륨티타닐옥살레이트의 제조방법.The barium compound solution is prepared by dissolving at least one barium compound selected from the group consisting of barium chloride (BaCl 2 ), barium nitrate (Ba (NO 3 ) 2 ) and barium perchlorate (Ba (ClO 4 ) 2 ) in water. The titanium compound solution is prepared by dissolving at least one titanium compound of titanium oxychloride (TiOCl 2 ) and titanium tetrachloride (TiCl 4 ) in water, and the oxalic acid solution is prepared by dissolving oxalic acid in water. Method for producing barium titanyl oxalate.
  3. 제1항에 있어서,The method of claim 1,
    상기 BTO 합성단계는 20~100℃의 합성온도에서 수행되는 바륨티타닐옥살레이트의 제조방법.The BTO synthesis step is a method for producing barium titanyl oxalate carried out at a synthesis temperature of 20 ~ 100 ℃.
  4. 제1항에 있어서,The method of claim 1,
    상기 BTO 건식분쇄단계는 해머밀, 기류분급분쇄기(ACM) 및 제트밀로 이루어진 군으로부터 선택된 적어도 1종의 분쇄기를 사용하여 실시되는 바륨티타닐옥살레이트의 제조방법.The BTO dry grinding step is a method for producing barium titanyl oxalate carried out using at least one mill selected from the group consisting of a hammer mill, an air flow classification mill (ACM) and a jet mill.
  5. 제1항에 있어서,The method of claim 1,
    상기 건식분쇄된 BTO는 2.5㎛ 이하의 입경(PSA D50) 및 8.0㎛ 이하의 입경(PSA D90)을 갖는 바륨티타닐옥살레이트의 제조방법.The dry milled BTO has a particle size of 2.5 μm or less (PSA D50) and a particle size of 8.0 μm or less (PSA D90).
  6. 제1항에 있어서,The method of claim 1,
    상기 BTO 합성단계와 상기 BTO 습식분쇄단계 사이에,Between the BTO synthesis step and the BTO wet grinding step,
    상기 합성된 BTO를 숙성하는 단계; Aging the synthesized BTO;
    상기 숙성된 BTO를 여과하는 단계; 및 Filtering the aged BTO; And
    상기 여과된 BTO를 과량의 물로 세정하는 단계를 더 포함하는 바륨티타닐옥살레이트의 제조방법.The method for producing barium titanyl oxalate further comprises the step of washing the filtered BTO with excess water.
  7. 제1항 내지 제6항 중 어느 한 항에 따라 제조된 BTO를 800~1000℃에서 열처리하여 티탄산바륨[BaTiO3](이하, 간단히 BT라고 함)을 합성하는 단계(BT 합성단계)를 포함하는 티탄산바륨의 제조방법.Claim 1 to claim 6 wherein the BTO prepared according to any one of the heat treatment at 800 ~ 1000 ℃ comprising the step of synthesizing barium titanate [BaTiO 3 ] (hereinafter, simply referred to as BT) (BT synthesis step) Method for producing barium titanate.
  8. 제7항에 있어서,The method of claim 7, wherein
    상기 BT 합성단계 이후에, 상기 합성된 BT를 분쇄하는 단계(BT 분쇄단계)를 더 포함하는 티탄산바륨의 제조방법.After the BT synthesis step, the method of producing barium titanate further comprising the step of grinding the synthesized BT (BT grinding step).
  9. 제7항의 제조방법에 의해 제조된 티탄산바륨.Barium titanate prepared by the process of claim 7.
  10. 제9항에 있어서,The method of claim 9,
    상기 티탄산바륨으로 이루어진 티탄산바륨 분말이 10중량% 이하의 응집체를 포함하는 티탄산바륨.A barium titanate comprising barium titanate powder composed of barium titanate containing 10% by weight or less of aggregates.
PCT/KR2013/010812 2013-11-26 2013-11-26 Method for preparing barium titanyl oxalate, method for preparing barium titanate, and barium titanate WO2015099203A1 (en)

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KR950013072B1 (en) * 1986-10-18 1995-10-24 Philips Nv Process for the preparation of barium titanate batio3
KR20020013382A (en) * 2000-08-09 2002-02-20 이형도 A Method for Producing Barium Titanate Based Powder by Oxalate Process
KR100434883B1 (en) * 2001-08-14 2004-06-07 삼성전기주식회사 A method for the manufacturing of Barium-Titanate based Powder
US7001585B2 (en) * 2003-04-23 2006-02-21 Ferro Corporation Method of making barium titanate
KR20100118805A (en) * 2009-04-29 2010-11-08 삼성정밀화학 주식회사 A method of preparing barium titanate powder by oxalate process and barium titanate powder prepared by same

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Publication number Priority date Publication date Assignee Title
KR950013072B1 (en) * 1986-10-18 1995-10-24 Philips Nv Process for the preparation of barium titanate batio3
KR20020013382A (en) * 2000-08-09 2002-02-20 이형도 A Method for Producing Barium Titanate Based Powder by Oxalate Process
KR100434883B1 (en) * 2001-08-14 2004-06-07 삼성전기주식회사 A method for the manufacturing of Barium-Titanate based Powder
US7001585B2 (en) * 2003-04-23 2006-02-21 Ferro Corporation Method of making barium titanate
KR20100118805A (en) * 2009-04-29 2010-11-08 삼성정밀화학 주식회사 A method of preparing barium titanate powder by oxalate process and barium titanate powder prepared by same

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