KR101548746B1 - A method of preparing barium titanate powder by oxalate process and barium titanate powder prepared by same - Google Patents

Abstract

A process for producing barium titanate powder by an oxalate process and a barium titanate powder produced by the process are disclosed. The disclosed method for producing a barium titanate powder includes the steps of adding an amino acid compound and a carboxylate group-containing compound to barium titanyl oxalate synthesized after synthesis of barium titanyl oxalate, followed by wet pulverization and spray drying. In addition, the barium titanate powder produced by the above-described production method has fine particle size distribution and high crystallinity.

Description

[0001] The present invention relates to a method for producing barium titanate powder by an oxalate process and a barium titanate powder prepared by the method,

A method for producing barium titanate powder and barium titanate powder produced by the method are disclosed. More specifically, the present invention relates to a process for producing barium titanyl oxalate, which comprises adding an amino acid compound and a carboxylate group-containing compound to barium titanyl oxalate synthesized after the synthesis of barium titanyl oxalate, wet pulverizing and spray- A method for producing barium powder and barium titanate powder produced by the method are disclosed.

BACKGROUND ART Recently, barium titanate for MLCC has been found to have a high dielectric constant (dielectric constant), a low dielectric constant (dielectric constant) and a high dielectric constant Atomization is required. However, as the barium titanate becomes finer, the crystallinity is lowered and the dielectric constant is lowered. Therefore, it has been difficult to lower the particle diameter to 300 nm or less in the conventional manufacturing method.

In order to solve these problems, Korean Patent Laid-Open Publication No. 2005-0081316 discloses a method for producing ultrafine barium titanate by improving the conventional coprecipitation method (or oxalate processing method). Specifically, the method is a method of producing ultrafine barium titanate by adding a metal-containing additive to the process of pulverizing barium titanyl oxalate followed by pulverization thereof. However, in the case of this method, it is possible to produce ultrafine, uniform barium titanate, but it is impossible to produce barium titanate having a high crystallinity because when barium titanyl oxalate is pulverized by adding a metal- The barium titanate having a high crystallinity is converted into barium titanate having a cubic crystal structure and the crystallinity is deteriorated when the barium titanate after the pulverization is synthesized. Accordingly, when the barium titanate produced by the above method is employed in MLCC, the dielectric constant of the MLCC is lowered, which makes it difficult to miniaturize the MLCC.

  Journal of Alloys and Compounds, 434-435 (2007), p. 688-772, discloses a method for preparing barium titanate which is improved from the existing solid phase method. According to the above method, barium titanate having a higher crystallinity than that of the existing solid phase method can be obtained by adding various additives when mixing barium carbonate and titanium dioxide to lower the dissociation temperature (that is, decomposition temperature) of barium carbonate. However, the barium titanate produced by the above method has a crystallinity of less than 1.0100 at 200 nm and less than 1.0095 at 100 nm. Therefore, barium titanate is not suitable for use in MLCC, and mass production of barium titanate by the above- And the stability of the Ba / Ti molar ratio is not suitable.

One embodiment of the present invention relates to an oxalate process comprising a step of adding an amino acid compound and a carboxylate group-containing compound to the synthesized barium titanyl oxalate after the synthesis of barium titanyl oxalate, wet pulverizing and spray drying And a method for producing the barium titanate powder.

Another embodiment of the present invention provides a barium titanate powder having a fine particle size distribution and a high crystallinity prepared by the above production method.

According to an aspect of the present invention,

A step of preparing an aqueous solution of barium chloride (BaCl ₂ ) and an aqueous solution of titanium tetrachloride (TiCl ₄ ) (raw material aqueous solution preparation step);

To form a first barium titanyl oxalate [BTO: BaTiO (C ₂ O ₄ ) ₂ .4H ₂ O] slurry by adding the aqueous solutions to an aqueous solution of oxalic acid (H ₂ C ₂ O ₄ ) step);

Mixing the BTO, the amino acid compound and the carboxylate group-containing compound in the first BTO slurry to form a second BTO slurry, followed by wet pulverizing the BTO in the second BTO slurry;

Spray drying the third BTO slurry formed after the wet pulverization to obtain a BTO-containing powder (drying step); And

Treating the dried BTO-containing powder to produce barium titanate (BT) (BT production step).

Wherein the amino acid compound is selected from the group consisting of glycine, alanine, valine, leucine, isoleucine, threonine, serine, cysteine, methionine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, arginine, histidine, phenylalanine, tyrosine, tryptophan and proline And may include at least one species.

The amount of the amino acid compound added may be 100 to 1,500 parts by weight based on 100 parts by weight of the BTO.

The carboxylate group-containing compound may include at least one member selected from the group consisting of higher fatty acid alkali salts (soap), N-acrylamino acid salts, alkyl ether carboxylates, and acylated peptides.

The carboxylate group-containing compound may be added in an amount of 50 to 500 parts by weight based on 100 parts by weight of the BTO.

The method for producing the barium titanate powder may further comprise, between the BTO producing step and the wet pulverizing step, aging the BTO produced, filtering the aged BTO, and washing the filtered BTO with excess water As shown in FIG.

The method for producing barium titanate powder may further include pulverizing barium titanate produced in the BT producing step.

According to another aspect of the present invention,

And barium titanate powder prepared by the above production method.

According to one embodiment of the present invention, there is provided a process for producing barium titanyl oxalate, which comprises adding barium titanyl oxalate synthesized after the synthesis of barium titanyl oxalate to an amino acid-based compound and a carboxylate group-containing compound, followed by wet pulverization and spray drying A process for producing barium titanate powder by a rate process can be provided. According to the above production method, barium titanate powder having a fine particle size distribution and a high crystallinity can be produced even in the case of mass production of barium titanate because sensitivity to heat treatment temperature is not so high.

According to another embodiment of the present invention, barium titanate powder having a fine particle size distribution and a high crystallinity can be prepared by the above production method.

Hereinafter, a method for producing barium titanate powder according to an embodiment of the present invention will be described in detail.

First, an aqueous solution of barium chloride (BaCl ₂ ) and an aqueous solution of titanium tetrachloride (TiCl ₄ ) are prepared (raw material aqueous solution preparation step). The aqueous barium chloride solution is usually prepared by dissolving BaCl ₂ .2H ₂ O in water, and its concentration range may be from 0.2 to 2.0 mol / l. When the concentration of barium chloride aqueous solution is less than 0.2 mol / l, the productivity of barium titanate described below is low compared to the volume of barium chloride aqueous solution. When the concentration exceeds 2.0 mol / l, the solubility range of barium chloride There is a possibility that barium chloride will precipitate out. The titanium tetrachloride aqueous solution is usually diluted with a high concentration titanium tetrachloride solution, and its concentration range may be from 0.2 to 2.0 mol / l. When the concentration of the titanium tetrachloride aqueous solution is less than 0.2 mol / l, the productivity of barium titanate is low relative to the volume of the aqueous titanium tetrachloride solution. When the concentration exceeds 2.0 mol / l, the solubility of titanium tetrachloride There is a possibility of titanium precipitation. The aqueous barium chloride solution and the aqueous titanium tetrachloride solution may be mixed in a ratio of 1 to 1.5, for example, 1 to 1.1, based on the molar ratio (barium chloride / titanium tetrachloride). When the molar ratio is less than 1, there is a high possibility that the molar ratio of barium titanate as the final product is lowered to less than 1. When the molar ratio exceeds 1.5, a second phase (another phase other than barium titanate, Ba ₂ TiO ₉ ) is produced. When the molar ratio of the final product barium titanate is lowered to less than 1, generation of the second phase and abnormal grain growth are caused.

Next, a mixed aqueous solution of the aqueous solution of barium chloride and aqueous solution of titanium tetrachloride or an aqueous solution of each of them is dropped into an aqueous solution of oxalic acid (H ₂ C ₂ O ₄ ) using a high-speed spray nozzle to obtain a first barium titanyl oxalate [BTO: BaTiO (C ₂ O ₄ ) ₂ .4H ₂ O] slurry (first BTO slurry production step). At this time, the oxalic acid aqueous solution may be used in a larger amount than the aqueous solution of barium chloride or aqueous solution of titanium tetrachloride. The concentration range of the oxalic acid aqueous solution may be 0.2 to 5.0 mol / l. If the concentration of oxalic acid aqueous solution is less than 0.2 mol / l, the productivity of barium titanate is low relative to the volume of oxalic acid aqueous solution. If the concentration exceeds 5.0 mol / l, the solubility of oxalic acid in water may be out of the range. Also in this case, the temperature of the oxalic acid aqueous solution may be maintained at 20 to 100 ° C, for example, 50 to 90 ° C. The time for which the aqueous solution of barium chloride and the aqueous solution of titanium tetrachloride are injected into the oxalic acid aqueous solution separately in the form of a mixed solution or separately is 1 to 3 hours. This drop time can be achieved by adjusting the injection speed of the nozzle. Injection nozzles can use a first-flow or second-flow nozzle depending on the flow of the fluid, and the use of a first-flow nozzle may be more advantageous in terms of convenience and obtaining uniform sediment. The first nozzle may be a full con, a hollow con or a flat nozzle. The process of adding the aqueous barium chloride solution and the aqueous titanium tetrachloride solution to the aqueous oxalic acid solution to produce the first BTO slurry can be represented by the following reaction formula 1.

[Reaction Scheme 1]

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

Next, the produced BTO can be aged, filtered, and then washed with water. The aging time is preferably 0.5 to 2 hours in terms of productivity. Here, filtration refers to a process of separating only solid phase BTO from the first BTO slurry using a centrifugal separator. The filtered BTO can then be washed with excess water until the pH of the wash is neutral.

Next, BTO obtained through the above process is wet pulverized (wet pulverization step). Herein, the wet grinding is performed by introducing BTO together with a predetermined medium into a wet pulverizer such as a beads mill, a ball mill and an attrition mill to form a second BTO slurry, 2 BTO " means wet pulverization of BTO in slurry. Here, the medium means water such as an organic solvent such as alcohol and deionized water. If an organic solvent is used, it is advantageous from the viewpoint of grinding efficiency and particle size control, but the cost is increased. This has the advantage of simplifying the process and reducing costs. When water is used as the medium, its amount may be 100-1,000 parts by weight based on 100 parts by weight of BTO. If the amount of the water used is less than 100 parts by weight, the powder can not be pulverized due to an increase in viscosity. If the amount is more than 1,000 parts by weight, the productivity of BTO is low compared with the volume of water. The milling time needs to be appropriately controlled by the difference in milling power depending on the milling equipment, and it may be 10 to 300 minutes when using the bead mill. By controlling the milling time in this way, the particle size of the final product, barium titanate powder, can be appropriately controlled.

Amino acid-based compounds and carboxylate group-containing compounds are added to such second BTO slurry. That is, an amino acid compound and a carboxylate group (-COO ^- ) -containing compound are introduced and mixed together with the BTO and the medium in the wet pulverizer, followed by pulverization.

The amino acid-based compound means a compound containing both an amino group (-NH ₂ ) and a carboxyl group (-COOH). The amino group and the carboxyl group contained in the amino acid compound increase the nucleation rate of barium titanate by promoting dissociation of CO and CO ₂ contained in BTO when barium titanate is produced by heat treatment of BTO, And serves to uniformize the particle size distribution. These amino acid compounds may be selected from the group consisting of glycine, alanine, valine, leucine, isoleucine, threonine, serine, cysteine, methionine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, arginine, histidine, phenylalanine, tyrosine, tryptophan, And mixtures thereof. The amount of the amino acid compound added may be 1 to 15 parts by weight based on 100 parts by weight of the BTO. If the amount of the amino acid compound added is less than 1 part by weight based on 100 parts by weight of the BTO, the addition effect is insignificant. If the amount is more than 15 parts by weight, an additional effect is not expected to be expected, .

The carboxylate group-containing compound plays a role in helping BTO, medium and amino acid-based compounds to mix uniformly with each other. Since the viscosity of BTO slurry formed by mixing conventional BTO with the medium is very high (viscosity of BTO slurry formed by mixing 100 parts by weight of BTO and 300 parts by weight of water is measured using Brookfield DV Ⅲ in LV2 spindle at rpm 1 The viscosity is 20,000 mPa · s or more), and the amino acid compound added to the BTO slurry is not uniformly mixed with BTO. Therefore, when only the amino acid compound is added and mixed in the BTO slurry without adding the carboxylate group-containing compound, nonuniform mixing is caused, and the particle size of the finally produced barium titanate is increased and the uniformity is lowered. For this reason, the carboxylate group-containing compound is added in the wet pulverization step to lower the viscosity of the second BTO slurry. Such carboxylate group-containing compounds may include higher fatty acid alkali salts (soaps), N-acrylamino acid salts, alkyl ether carboxylic acid salts, acylated peptides, and mixtures of two or more thereof. The carboxylate group-containing compound may be added in an amount of 50 to 500 parts by weight based on 100 parts by weight of the BTO. If the addition amount of the carboxylate group-containing compound is less than 50 parts by weight based on 100 parts by weight of the BTO, the addition effect is insignificant. If the addition amount exceeds 500 parts by weight, further effect is not expected to be expected. It is not removed.

Next, the third BTO slurry (= wet pulverized BTO + amino acid compound + carboxylate group-containing compound + medium) formed after wet pulverization is dried at a temperature of 250 DEG C or less to remove the medium contained in the mixture Drying step). When the drying temperature exceeds 250 ° C, the amino group and / or the carboxyl group contained in the amino acid compound decompose and the original effect of the amino acid compound exerted can not be obtained. In this case, it is natural that the drying temperature should be equal to or higher than the boiling point of the medium in order to evaporate and remove the used medium. In addition, the drying step is performed by spray drying or the like, which is a drying method in which BTO and amino acid-based compounds are not separated by drying. If VAT drying, which is a conventional drying method, or VAT drying after filter pressing, separation of BTO and an amino acid compound occurs, barium titanate having a uniform particle size distribution can not be obtained. VAT Drying refers to drying out of big tits. As a result, a dried BTO-containing powder (= BTO + amino acid compound + carboxylate group-containing compound) is obtained. The BTO-containing powder is a mixture of BTO and an amino acid compound and a carboxylate group-containing compound.

Then, the dried BTO-containing powder is heat-treated to produce barium titanate (BT production step). At this stage, as described above, the amino acid-based compound contained in the BTO-containing powder accelerates the dissociation of CO and CO ₂ contained in the BTO in the heat treatment process to increase the nucleation rate of barium titanate, Barium titanate can be prepared.

The heat treatment temperature may be 800 to 1,200 ° C. If the heat treatment temperature is lower than 800 ° C, barium titanate is hardly produced, which is not preferable. If the heat treatment temperature is higher than 1,200 ° C, barium titanate is excessively large in particle size. The temperature raising rate from the drying temperature to the heat treatment temperature may be 0.5 to 10 占 폚 / min, for example, 1 to 5 占 폚 / min. When the rate of temperature rise is less than 0.5 占 폚 / min, the productivity of barium titanate is lowered. When the heating rate is more than 10 占 폚 / min, the temperature distribution is not uniform and the particle size of barium titanate becomes uneven. By performing the heat treatment as described above, water and excess carbon dioxide gas present in the crystal water as the crystal water are removed, and barium titanate powder having a size of several tens to several hundreds of nanometers is obtained through the process of the following Reaction Schemes 2 to 4.

[Reaction Scheme 2]

BaTiO (C ₂ O ₄ ) ₂ .4H ₂ O? BaTiO (C ₂ O ₄ ) ₂ + 4H ₂ O

[Reaction Scheme 3]

BaTiO (C ₂ O ₄ ) ₂ + 1/2 O _{2 -} > BaCO ₃ + TiO ₂ + 2CO ₂

[Reaction Scheme 4]

BaCO ₃ + TiO _{2 -} > BaTiO ₃

A sagger or a tray may be used as a heating furnace for heat-treating the dried BTO-containing powder. Here, Sagger refers to refractory earth containers. The sagger may be, for example, a hexagonal container having a square bottom surface.

Thereafter, the barium titanate produced through the heat treatment process (i.e., the BT production process) may be pulverized, but such a pulverization process may be omitted. The pulverization may be carried out by wet pulverization using a pulverizer such as a beads mill, an atrition mill, and a ball mill together with a predetermined medium, a jet mill and a disk mill Disk mill or the like may be used for the pulverization between the raw materials without using the medium or the dry grinding using the frictional force with the grinder. The pulverization step is intended to solve the intergranular agglomeration of the barium titanate powder. After the wet pulverization, a drying process is additionally required, but it is not necessary to use facilities specially limited for drying. In the case of using an apparatus having an excessively high grinding efficiency in the grinding step, the grinding strength is lowered as much as possible to reduce the grain size distribution and crystallinity, It is preferable to cut only the necking between the particles without destroying the particles.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

Example

Example 1

(BTO crystal formation and aging)

The titanium tetrachloride aqueous solution of barium chloride aqueous solution 1.0L 1.2L with 1mol / L concentration of 1mol / L concentration 4M ³ Glass-mix well in line (Glass-lined) reaction vessel made of a mixed aqueous solution. Then, the mixed aqueous solution was injected into a reactor filled with 2.0 L of an oxalic acid aqueous solution having a concentration of 2 mol / L into the reactor at a rate of 20 mL / min using a full cone type nozzle and mixed. Two non-pulsating pumps (L / S Digital standard pump of Fondo Corp.) were used to supply the mixed aqueous solution when injecting the nozzles. When the mixed aqueous solution and the oxalic acid aqueous solution were mixed, the synthesis temperature was set to 65 ° C, and after the mixing was completed, the mixture was kept at the above temperature for 30 minutes and aged. As a result, a first BTO slurry was obtained.

(Filtration and washing of the resulting first BTO slurry)

The first BTO slurry prepared above was filtered with a centrifuge and washed with excessive water to a pH of the washing solution of 4 or more to obtain a BTO crystal mass.

(Wet grinding and drying of the resulting BTO crystal mass)

1 kg of BTO, 3 kg of deionized water, 0.01 kg of glycine and 0.05 kg of a carboxylate group-containing compound (KAO, POIZ532A) were added to a mixing vessel and stirred to produce a second BTO slurry. Thereafter, the second BTO slurry was wet pulverized so as to have a maximum particle diameter of 3 mu m or less with a 1 L horizontal volume type bead mill. The viscosity of the third BTO slurry formed after milling (LV2 spindle using Brookfield DV III, measured at rpm 1) was 12,000 mPa · s. The thus-obtained third BTO slurry was spray-dried to obtain a BTO-containing powder.

(Heat treatment)

The dried BTO-containing powder was charged in a 1,000 cm ³ sagger and subjected to heat treatment at a temperature of 900 ° C. As a result, barium titanate was obtained. The crystallization degree (c / a), the average particle size and the particle size distribution (D ₁₀ / D ₅₀ , D ₅₀ / D ₉₀ ) of the barium titanate crystals were measured with the temperature employed in the heat treatment.

The crystallinity (c / a) was determined by measuring XRD (D / Max 2000 series by Rigaku) at 40 kV, 200 mA at a rate of 2 sec / step and 0.02 step size, And the d-spacing values of the a-axis and the c-axis of the barium titanate were measured. D ₁₀ / D ₅₀ and D ₅₀ / D _{90, which} are the indexes of the average particle size and the particle size distribution, were measured by scanning electron microscope (SEM) photographs using a JSM-7400F manufactured by Jeol Co., Pro Plus ver 4.5) was used to calculate the size of the barium titanate particles on the average of the major axis and the minor axis of the barium titanate particles. The number of barium titanate particles measured was 800 or more. Here, the larger the D ₁₀ / D ₅₀ and the D ₅₀ / D ₉₀ , the better the particle size distribution. Here, D _10, D _{50, and} D ₉₀ represent the particle diameters of particles corresponding to the order of 10%, 50%, and 90%, respectively, of the total number of particles when the measured particles are arranged in order from smallest to largest. do. In addition, photographs of barium titanate prepared in Example 1 and Comparative Example 1 of the SEM photographs are shown in FIGS. 1A and 1B, respectively.

Example  2 to 5

The same procedure as in Example 1 was carried out except that the amount of the glycine and carboxylate group-containing compound and / or the drying method in the wet pulverization step of BTO were changed as shown in the following Table 1 according to the respective examples (C / a), average particle diameter and particle size distribution (D ₁₀ / D ₅₀ , D ₅₀ / D ₉₀ ) of barium titanate crystals were measured. The results are shown in Table 1 below. In addition, the viscosity of the third BTO slurry formed after wet pulverization was measured and is shown in Table 1 below.

Comparative Example  1-4

Barium titanate was prepared in the same manner as in Example 1 except that at least one of glycine and carboxylate group-containing compounds was not added in the wet pulverization step of BTO (see Table 1 below), and barium titanate crystals (C / a), average particle size and particle size distribution (D ₁₀ / D ₅₀ , D ₅₀ / D ₉₀ ) In addition, the viscosity of the third BTO slurry formed after wet pulverization was measured and is shown in Table 1 below. The VAT drying of Comparative Examples 3 and 4 was carried out at 120 DEG C for 24 hours using an electric oven, and a vacuum filtration device (manufactured by Samsung Fine Chemicals Co., Ltd.) was used for compression filtration of Comparative Example 4. [

Referring to Table 1, barium titanate in Examples 1 to 5 was uniform in particle size distribution, and had a higher degree of crystallinity and a smaller average particle size than barium titanate in Comparative Examples 1 to 4. These results become more apparent when the FIGS. 1A and 1B are observed.

Examples 6 to 7

Barium titanate was prepared in the same manner as in Example 1 except that the heat treatment temperature was changed (see Table 2 below), and the barium titanate crystals were measured for crystallinity (c / a), average particle size The change rate of the particle diameter is measured or calculated and is shown in Table 2 below. In addition, the viscosity of the third BTO slurry formed after wet pulverization was measured and is shown in Table 2 below. The data of Example 1 was also added to Table 2 for comparison.

Examples 8 to 9

Barium titanate was prepared in the same manner as in Example 3 except that the heat treatment temperature was changed (see Table 2 below), and the barium titanate crystals were measured for crystallinity (c / a), average particle diameter The change rate of the particle diameter is measured or calculated and is shown in Table 2 below. In addition, the viscosity of the third BTO slurry formed after wet pulverization was measured and is shown in Table 2 below. The data of Example 3 was also added to Table 2 for comparison.

Comparative Examples 5 to 6

Barium titanate was prepared in the same manner as in Comparative Example 2 except that the heat treatment temperature was changed (see Table 2 below), and the barium titanate crystal thus prepared was evaluated for crystallinity (c / a) The change rate of the particle diameter is measured or calculated and is shown in Table 2 below. In addition, the viscosity of the third BTO slurry formed after wet pulverization was measured and is shown in Table 2 below. The data of Comparative Example 2 was also added to Table 2 for comparison.

It can be seen that Examples 1, 6 and 7 and Examples 3, 8 and 9 have a smaller rate of change of the average particle diameter depending on the heat treatment temperature than Comparative Examples 2, 5 and 6. Further, when Examples 1, 6, 7 and Examples 3, 8, and 9 are compared with each other, it can be seen that as the amount of glycine added increases, the rate of change of the average particle diameter decreases with the heat treatment temperature. Therefore, according to the method for producing barium titanate powder according to an embodiment of the present invention, the average particle diameter of barium titanate produced even in the case of mass production does not react sensitively to the temperature deviation of the heat treatment furnace, And manufacturing becomes possible.

 FIG. 2 is a graph showing the rate of change of the average particle diameter according to the heat treatment temperature by the addition amount of glycine. In FIG. 2, 1% of glycine represents Examples 6, 1 and 7, 10% of glycine represents Examples 8, 3 and 9, and 0% of glycine corresponds to Comparative Example 5 , 2, and 6, respectively.

 While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is an SEM photograph of barium titanate particles prepared by the method of producing barium titanate according to an embodiment of the present invention (Example 1), and FIG. 1B is a SEM photograph of barium titanate particles produced by the method of manufacturing barium titanate SEM photograph of barium particles (Comparative Example 1).

 FIG. 2 is a graph showing the rate of change of the average particle diameter according to the heat treatment temperature by the addition amount of glycine.

Claims (8)

A step of preparing an aqueous solution of barium chloride (BaCl ₂ ) and an aqueous solution of titanium tetrachloride (TiCl ₄ ) (raw material aqueous solution preparation step); To form a first barium titanyl oxalate [BTO: BaTiO (C ₂ O ₄ ) ₂ .4H ₂ O] slurry by adding the aqueous solutions to an aqueous solution of oxalic acid (H ₂ C ₂ O ₄ ) step); Mixing the BTO, the amino acid compound and the carboxylate group-containing compound in the first BTO slurry to form a second BTO slurry, followed by wet pulverizing the BTO in the second BTO slurry; Spray drying the third BTO slurry formed after the wet pulverization to obtain a BTO-containing powder (drying step); And Treating the dried BTO-containing powder to produce barium titanate (BT producing step). The method according to claim 1, Wherein the amino acid compound is selected from the group consisting of glycine, alanine, valine, leucine, isoleucine, threonine, serine, cysteine, methionine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, arginine, histidine, phenylalanine, tyrosine, tryptophan and proline And at least one barium titanate powder. The method according to claim 1, Wherein the amino acid compound is added in an amount of 1 to 15 parts by weight based on 100 parts by weight of the BTO. The method according to claim 1, Wherein the carboxylate group-containing compound comprises at least one member selected from the group consisting of a higher fatty acid alkali salt (soap), an N-acrylamino acid salt, an alkyl ether carboxylic acid salt, and an acylated peptide. The method according to claim 1, Wherein the carboxylate group-containing compound is added in an amount of 50 to 500 parts by weight based on 100 parts by weight of the BTO. The method according to claim 1, Between the BTO generation step and the wet grinding step, Aging the resultant BTO; Filtering the aged BTO; And ≪ / RTI > further comprising washing the filtered BTO with excess water. The method according to claim 1, And b) grinding the barium titanate produced in the BT production step. delete

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