A preparation method of electronic grade barium carbonate

Abstract

The present invention relates to the technical field of barium carbonate, and specifically proposes a method for preparing electronic-grade barium carbonate, comprising: mixing a barium salt solution with a carbonate solution, and performing a double decomposition reaction; during the double decomposition reaction, periodically adjusting the pH value of the reaction system so that it fluctuates within the range of 6.0-9.0, with a fluctuation period of 10-60 min, a fluctuation cycle number of not less than 2 times, and a fluctuation being a process in which the pH value is adjusted from a minimum value to a maximum value and then adjusted to a minimum value; after the reaction is completed, solid-liquid separation, washing, drying, and electronic-grade barium carbonate are obtained. The present application adopts a dynamic pH oscillation method, which significantly improves the purity and morphology control level of electronic-grade barium carbonate. Dynamic pH fluctuations interfere with the growth of crystal nuclei without the need for growth, making it easier for crystal nuclei to form crystalline spherical or cubic particles, with a higher size concentration, substantially no additional impurities are introduced, and the post-processing steps are simple and efficient, with good application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of barium carbonate, and in particular to a method for preparing electronic-grade barium carbonate. Background Art

[0002] Electronic-grade barium carbonate requires extremely high purity, and impurities such as Fe, Ca, and Sr must be controlled to the ppm level. Traditional processes struggle to meet these requirements due to issues such as insufficient raw material purity, impurities introduced during the reaction, and incomplete washing.

[0003] Some electronic components, such as MLCC, require barium carbonate particles to be spherical or nearly spherical, and have a narrow particle size distribution. The traditional carbonization method easily produces rod-shaped particles with a relatively wide particle size distribution, which leads to unstable dielectric properties. In order to solve these technical problems, the existing technology has also adopted some different improvement schemes, such as multi-stage crystallization, ion exchange or fluoride salt removal, etc., but these methods will not only increase production costs, make the preparation steps more complicated, but also may introduce new impurities. In some schemes, deionized water will be used for multiple rinses and complexing agents will be added to remove residual metal impurities, but this will introduce new organic impurities. Although fluoride salts can precipitate impurity ions, they will introduce fluoride ion contamination. Conventional morphology control additives, such as surfactants, are generally unable to directionally regulate crystal growth, resulting in difficult to control particle morphology.

[0004] Based on this, how to optimize the preparation process so that impurities can be controlled more efficiently has become one of the technical problems that need to be solved urgently. Summary of the Invention

[0005] In view of this, the present invention proposes a method for preparing electronic-grade barium carbonate, which enhances the desorption of impurities and improves the purity by oscillating the pH.

[0006] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing electronic grade barium carbonate, comprising the following steps:

[0007] Step 1: mixing a barium salt solution with a carbonate solution to perform a double decomposition reaction;

[0008] Step 2: During the double decomposition reaction, the pH value of the reaction system is periodically adjusted so that it fluctuates within the range of 6.0-9.0, with a fluctuation period of 10-60 minutes and a fluctuation cycle of not less than 2 times. A fluctuation is a process in which the pH is adjusted from the lowest value to the highest value and then to the lowest value;

[0009] Step 3: After the reaction is completed, the solid and liquid are separated, washed and dried to obtain electronic grade barium carbonate.

[0010] Existing technologies often use constant pH conditions, where crystal nuclei grow randomly. The aforementioned implementation utilizes pH fluctuations to alter the surface charge of the particles, enhancing electrostatic repulsion and preventing particle agglomeration. The acid-base colloidal environment can interfere with the crystal growth rate, forcing the particles to align into spherical or cubic shapes.

[0011] In some embodiments, in step 2, before adjusting the pH, a crystal form control agent is further added, wherein the crystal form control agent is at least one of a surfactant and an ionic liquid, and the addition amount is 0.1-5% of the total mass of the reaction solution.

[0012] In the above embodiment, surfactants or ionic liquids can regulate the interfacial energy of crystal nucleus growth by adsorbing on the particle surface. Surfactants can reduce surface tension and inhibit particle agglomeration through physical adsorption, thereby further reducing the particle size. Ionic liquids can selectively regulate the growth of crystal surfaces through chemical bonding to achieve morphology control.

[0013] In some embodiments, the crystal form controlling agent is a bipolar ionic liquid, including a composite system of a Bronsted acidic ionic liquid and a bisulfate ionic liquid, and the molar ratio of the Bronsted acidic ionic liquid to the bisulfate ionic liquid is 1:(1-3).

[0014] The dihydrogen phosphate in the Bronsted acidic ionic liquid can release protons, thereby complexing metal impurities such as iron ions and reducing lattice defects. The hydrogen sulfate in the bisulfate ionic liquid adsorbs on the (110) crystal plane through its strong coordination ability, inhibiting its growth. The two can synergistically increase the proportion of the (104) crystal plane and significantly reduce the content of impurity ions.

[0015] In some embodiments, the Bronsted acidic ionic liquid is 1-butyl-3-methylimidazolium dihydrogen phosphate, and the bisulfate ionic liquid is 1-butyl-3-methylimidazolium bisulfate.

[0016] As a concrete and feasible compound system with good results, acidic anions (H2PO4 - ) preferentially adsorbs on high-energy crystal faces (such as (104)), inhibiting their growth and promoting the exposure of low-energy crystal faces. - Stabilize the particle surface through electrostatic interaction to prevent disordered agglomeration. After compounding, the particle size distribution can be significantly optimized.

[0017] In some embodiments, in step 2, the pH value fluctuates within a range of 6.5-8.5.

[0018] The pH lower limit is set at 6.5 to avoid excessive acidity and Ba 2+The pH limit for dissolution is set at 8.5 to prevent excessive alkalinity from forming Ba(OH)2 impurities. Narrow fluctuation range reduces D50 and improves purity.

[0019] In some embodiments, in step 2, one fluctuation period is 15-30 minutes, and the number of fluctuation cycles is 3-5 times.

[0020] The above fluctuation period can match the growth dynamics of the crystal nucleus, and 3-5 cycles can ensure sufficient control of the crystal plane orientation.

[0021] In some embodiments, the barium salt solution is a barium chloride solution, and the barium salt solution is pretreated before mixing. The pretreatment method includes: adding citric acid or tartaric acid to the barium salt solution in an amount of 0.05-0.2% of the mass of the barium salt, stirring for 30-60 minutes and then filtering to obtain a clear barium salt solution.

[0022] The carboxylic acid group can complex iron ions and calcium ions to form soluble complexes, which can be removed by filtration. The iron ion concentration in the raw material liquid is reduced after pretreatment, thereby reducing the purification pressure of subsequent treatment.

[0023] In some embodiments, the washing in step three is a gradient temperature washing, which is sequentially washed with 80-90°C hot water once, 40-50°C warm water once, and 20-30°C cold water once, and the amount of washing liquid used each time is 2-5 times the weight of the solid.

[0024] Gradient washing is mainly used to enhance the removal of chloride ions while avoiding particle dissolution.

[0025] In some embodiments, after the solid-liquid separation in step 3, the centrifuged mother liquor is subjected to reduced pressure distillation to recover the bipolar ionic liquid.

[0026] By utilizing the low volatility of ionic liquids, the ionic liquids can be recycled and reused, reducing the cost of using additives.

[0027] In some embodiments, in step 2, the metathesis reaction temperature is 25-40°C, and the reaction temperature is adjusted simultaneously when the pH is adjusted. The reaction temperature at the highest pH value is 5-10°C higher than the reaction temperature at the lowest pH value.

[0028] pH oscillation is used to break the static reaction equilibrium and inhibit disordered growth. While oscillating, the reaction temperature is fine-tuned accordingly. For example, during the pH rising phase, increasing the temperature is beneficial to accelerate nucleation and enhance the ionic liquid adsorption efficiency, while during the pH falling phase, lowering the temperature can slow the growth rate and extend the time window for morphology control.

[0029] The present invention has the following beneficial effects compared to the prior art:

[0030] This application adopts a dynamic pH oscillation method to significantly improve the purity and morphology control level of electronic-grade barium carbonate. The dynamic pH fluctuation interferes with the growth of the crystal nucleus without requiring it to grow, making it easier for the crystal nucleus to form crystalline spherical or cubic particles with higher size concentration, which can meet the strict uniformity requirements of dielectric materials. In addition, the preparation method is simpler and basically does not introduce additional impurities. The post-processing steps are simple and efficient, and it has good application prospects. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present invention belong. If the definitions set forth in this section are contrary to or otherwise inconsistent with definitions set forth in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this section take precedence over the definitions incorporated herein by reference.

[0033] Unless otherwise specified, the methods used in the following examples are conventional methods. The materials, reagents, and instruments used are conventional materials, reagents, and instruments in the art, unless otherwise specified, and can be obtained commercially by those skilled in the art.

[0034] When an amount, concentration or other value or parameter is expressed as a range, a preferred range or a range defined by a series of upper preferred values and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed alone. For example, when a range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within the range. In the present specification and claims, range definitions may be combined and / or interchanged, and if not otherwise stated, such ranges include all subranges contained therein.

[0035] Example 1

[0036] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions.

[0037] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0038] Preparation by metathesis:

[0039] Mixing a barium chloride aqueous solution and a 20 wt% ammonium carbonate solution at a molar ratio of barium chloride to ammonium carbonate of 1:1;

[0040] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0041] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0042] Example 2

[0043] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and surfactants.

[0044] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0045] Preparation by metathesis:

[0046] Mixing a barium chloride aqueous solution and a 20 wt% ammonium carbonate solution at a molar ratio of 1:1, and then adding 0.8 wt% sodium hexametaphosphate to the mixed solution;

[0047] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0048] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0049] Example 3

[0050] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0051] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0052] Preparation by metathesis:

[0053] A barium chloride aqueous solution and a 20 wt % ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt % of a bipolar ionic liquid was added to the mixed solution. The bipolar ionic liquid was prepared by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:2;

[0054] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0055] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0056] Example 4

[0057] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0058] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0059] Preparation by metathesis:

[0060] A barium chloride aqueous solution and a 20 wt % ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt % of a bipolar ionic liquid was added to the mixed solution. The bipolar ionic liquid was prepared by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:2;

[0061] The initial pH of the mixed solution was adjusted to 6.5 with ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.5 to 8.5 within 15 min, and then to 6.5. This step was repeated three times.

[0062] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0063] Example 5

[0064] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0065] Raw material processing: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25wt% aqueous solution. Add 0.1wt% citric acid, stir for 45 minutes, and filter. The conductivity is less than 100μS / cm.

[0066] Preparation by metathesis:

[0067] The purified barium chloride aqueous solution was mixed with a 20 wt% ammonium carbonate solution at a molar ratio of 1:1, and then 0.8 wt% of a bipolar ionic liquid was added to the mixed solution. The bipolar ionic liquid was prepared by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:2;

[0068] The initial pH of the mixed solution was adjusted to 6.5 with ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 25°C. The pH was then adjusted from 6.5 to 8.5 within 15 min while the temperature was heated to 35°C at a rate of 1°C / min, then adjusted back to 6.5, and the temperature was simultaneously cooled to 25°C at a rate of 1°C / min. This step was repeated three times.

[0069] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0070] Example 6

[0071] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0072] Raw material processing: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25wt% aqueous solution. Add 0.1wt% citric acid, stir for 45 minutes, and filter. The conductivity is less than 100μS / cm.

[0073] Preparation by metathesis:

[0074] The purified barium chloride aqueous solution was mixed with a 20 wt% ammonium carbonate solution at a molar ratio of 1:1, and then 0.8 wt% of a bipolar ionic liquid was added to the mixed solution. The bipolar ionic liquid was prepared by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:2;

[0075] The initial pH of the mixed solution was adjusted to 6.5 with ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 25°C. The pH was then adjusted from 6.5 to 8.5 within 15 min while the temperature was slowly heated to 35°C, then adjusted to 6.5 again and cooled to 25°C. This step was repeated three times.

[0076] After centrifugation, the filter cake was washed once with 80°C hot water, then once with 45°C warm water, and then once with 25°C cold water, and dried to obtain barium carbonate. The filtrate was recovered by vacuum distillation at 60°C and -0.09MPa.

[0077] Example 7

[0078] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0079] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0080] Preparation by metathesis:

[0081] A barium chloride aqueous solution and a 20 wt % ammonium carbonate solution are mixed at a molar ratio of 1:1, and then 0.8 wt % of a bipolar ionic liquid is added to the mixed solution. The bipolar ionic liquid is obtained by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:1;

[0082] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0083] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0084] Example 8

[0085] This embodiment provides a method for preparing barium carbonate using pH oscillation conditions and a bipolar ionic liquid complex system.

[0086] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0087] Preparation by metathesis:

[0088] An aqueous barium chloride solution and a 20 wt % ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt % of a bipolar ionic liquid was added to the mixed solution. The bipolar ionic liquid was prepared by mixing 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate at a molar ratio of 1:3;

[0089] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0090] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0091] Comparative Example 1

[0092] This comparative example adopts a conventional metathesis reaction technical solution, and the metathesis reaction is carried out at a constant pH of 8.0.

[0093] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0094] Preparation by metathesis:

[0095] Mixing a barium chloride aqueous solution and a 20 wt% ammonium carbonate solution at a molar ratio of barium chloride to ammonium carbonate of 1:1;

[0096] The initial pH of the mixed solution was adjusted to 8.0 with ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L), the temperature was 30°C, and the reaction was kept at this temperature for 45 min.

[0097] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0098] Comparative Example 2

[0099] This comparative example adopts a conventional double decomposition reaction technical solution, the double decomposition reaction is carried out at a constant pH of 8.0, and sodium hexametaphosphate is added as a raw material.

[0100] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0101] Preparation by metathesis:

[0102] A barium chloride aqueous solution and a 20 wt % ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt % sodium hexametaphosphate was added to the mixed solution;

[0103] The initial pH of the mixed solution was adjusted to 8.0 with ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L), the temperature was 30°C, and the reaction was kept at this temperature for 45 min.

[0104] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0105] Comparative Example 3

[0106] This comparative example provides a method for preparing barium carbonate using pH oscillation conditions and ionic liquids.

[0107] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0108] Preparation by metathesis:

[0109] A barium chloride aqueous solution and a 20 wt% ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt% of an ionic liquid was added to the mixed solution, wherein the ionic liquid was 1-butyl-3-methylimidazole dihydrogen phosphate;

[0110] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0111] After centrifugation, the filter cake was washed three times with 25°C cold water and dried to obtain barium carbonate.

[0112] Comparative Example 4

[0113] This comparative example provides a method for preparing barium carbonate using pH oscillation conditions and ionic liquids.

[0114] Raw material treatment: Dissolve industrial-grade barium chloride (BaCl2·2H2O, purity 98%) in deionized water to prepare a 25 wt% aqueous solution.

[0115] Preparation by metathesis:

[0116] A barium chloride aqueous solution and a 20 wt% ammonium carbonate solution were mixed at a molar ratio of 1:1, and then 0.8 wt% of an ionic liquid was added to the mixed solution, wherein the ionic liquid was 1-butyl-3-methylimidazolium hydrogen sulfate;

[0117] The initial pH of the mixed solution was adjusted to 6.0 with aqueous ammonia (5 wt%) and dilute hydrochloric acid (0.1 mol / L) at 30°C. The pH was then adjusted from 6.0 to 9.0 within 15 min, and then to 6.0. This step was repeated three times.

[0118] After centrifugation, the filter cake was washed three times with cold water at 25°C and dried to obtain barium carbonate. The barium carbonate prepared in the above examples and comparative examples was tested for D50, D90 / D10 and impurity ions, and the following data were obtained:

[0119]

[0120] Compared with Example 3, Example 4 adopts a more preferred pH range, and its D50 particle size is smaller, indicating that the narrow range of pH fluctuation reduces particle dissolution and secondary nucleation, and improves morphology uniformity. The iron ion also drops from 10ppm to 8ppm, indicating that when the pH fluctuation range is too large, barium ions may be dissolved, resulting in an increase in adsorbed impurities. Example 5 adjusts the pH while also adjusting the temperature fluctuation. The heating stage may promote the diffusion of the ionic liquid and improve the adsorption efficiency, while the cooling stage prolongs the crystal surface control time, which is conducive to the increase in the proportion of the (104) crystal surface. After gradient washing, Example 6 not only reduces the D50 particle size, but also improves the proportion of the (104) crystal surface. At the same time, the content of each impurity component is significantly reduced. The recovered ionic liquid is subjected to secondary production. After 5 cycles, its recovery rate is still above 90%. The D50 particle size fluctuation of the prepared product is ≤0.02μm, which has significant economic value.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing electronic grade barium carbonate, characterized in that: The steps include: Step 1: mixing a barium salt solution with a carbonate solution to perform a double decomposition reaction; Step 2: During the metathesis reaction, 1-butyl-3-methylimidazolium dihydrogen phosphate and 1-butyl-3-methylimidazolium hydrogen sulfate are added in a molar ratio of 1:(1-3), and the pH value of the reaction system is periodically adjusted to fluctuate within the range of 6.5-8.5, with a fluctuation cycle of 15-30 minutes, and the fluctuation cycle is repeated 3-5 times, wherein the pH value is adjusted from the lowest value to the highest value and then to the lowest value; Step 3: After the reaction is completed, the solid and liquid are separated, washed and dried to obtain electronic grade barium carbonate.

2. The method for preparing electronic grade barium carbonate according to claim 1, wherein The barium salt solution is a barium chloride solution, and the barium salt solution is pretreated before mixing. The pretreatment method includes: adding citric acid or tartaric acid to the barium salt solution in an amount of 0.05-0.2% of the mass of the barium salt, stirring for 30-60 minutes and then filtering to obtain a clear barium salt solution.

3. The method for preparing electronic grade barium carbonate according to claim 1, wherein The washing in step 3 is a gradient temperature washing, which is washed with 80-90°C hot water once, 40-50°C warm water once, and 20-30°C cold water once. The amount of washing liquid used each time is 2-5 times the weight of the solid.

4. The method for preparing electronic grade barium carbonate as claimed in any one of claims 1 to 4, wherein: After solid-liquid separation in step 3, the centrifuged mother liquor is subjected to reduced pressure distillation to recover the bipolar ionic liquid.

5. The method for preparing electronic grade barium carbonate according to claim 1, wherein In step 2, the metathesis reaction temperature is 25-40° C., and the reaction temperature is adjusted simultaneously when the pH is adjusted. The reaction temperature at the highest pH value is 5-10° C. higher than the reaction temperature at the lowest pH value.

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