Method for purifying electronic-grade barium chloride

Abstract

The present application relates to the technical field of barium chloride production and preparation, and particularly relates to a purification method of electronic-grade barium chloride, comprising the following steps: S1, obtaining barium-containing filter residue by washing barite tailing barium residue with hydrochloric acid; S2, mixing the barium-containing filter residue and hydrochloric acid to perform leaching treatment, and obtaining barium chloride crude product; S3, dispersing the barium chloride crude product in water, adjusting the pH of the solution, adding a decontaminating agent, and performing ultrasonic-assisted segmented temperature control treatment, and obtaining barium chloride solution after filtration; S4, adding a crystal form control agent to the barium chloride solution, and performing programmed cooling crystallization under the action of a low-intensity direct current electric field to obtain electronic-grade barium chloride. The technical scheme of the present application realizes efficient conversion of difficult-to-treat barium residue and precise separation of impurities, overcomes technical problems such as low barium recovery rate, difficulty in removing impurities, and unstable product purity in traditional methods, and significantly improves the resource utilization rate of barium.

Description

Technical Field

[0001] This invention relates to the field of barium chloride production and preparation technology, and in particular to a method for purifying electronic-grade barium chloride. Background Technology

[0002] Barium chloride is an important chemical raw material widely used in electronics, ceramics, glass, and other fields. Traditional barium chloride production mainly uses natural barium minerals such as barite and barite as raw materials, producing barium carbonate through sodium carbonate reduction roasting, and then dissolving it in hydrochloric acid to obtain barium chloride. With the rapid development of the electronics industry, the demand for high-purity electronic-grade barium chloride is increasing, requiring a higher Fe content in the product. 3+ Ca 2+ 、Sr 2+ The extremely low content of impurity ions and the complete crystal structure pose higher technical requirements for the purification technology of barium chloride.

[0003] Existing barium chloride purification methods primarily target the quality improvement of industrial-grade products. For example, patent CN202311351272.1 discloses a purification method for industrial-grade barium chloride. This method first washes the industrial-grade barium chloride with an ethanol solution to remove some calcium, strontium ions, and water-soluble impurities. Then, it uses oxalic acid solution to react with the calcium and strontium ions in the barium chloride solution to form oxalate precipitate. Finally, it obtains high-purity barium chloride through crystallization. However, this technology still has significant shortcomings: firstly, the impurity removal methods of ethanol washing and oxalic acid precipitation are relatively simple, and are not suitable for Fe... 3+ The removal effect of polyvalent metal ions is limited; secondly, traditional crystallization processes make it difficult to precisely control crystal morphology and purity, and the final product can only reach the superior purity level, which cannot meet the strict requirements of electronic-grade barium chloride for ultra-low impurity content and high crystal quality. Summary of the Invention

[0004] In view of this, the present invention proposes a purification method for electronic-grade barium chloride to solve the technical problems of limited impurity removal effect and insufficient crystallization control precision in the prior art, which makes it impossible to prepare high-purity barium chloride products that meet electronic-grade standards.

[0005] The technical solution of this invention is achieved as follows: This invention provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0006] S1. Barium residue from barium tailings of toxic barite is treated with hydrochloric acid to obtain barium-containing filter residue.

[0007] S2. The barium-containing filter residue is mixed with hydrochloric acid and leached to obtain crude barium chloride.

[0008] S3. Disperse crude barium chloride in water, adjust the pH of the solution, add a purification agent, and process it by ultrasonic-assisted segmented temperature control. After filtration, a barium chloride solution is obtained.

[0009] S4. Add a crystal form control agent to the barium chloride solution and perform programmed cooling crystallization under a low-intensity DC electric field to obtain electronic-grade barium chloride.

[0010] Specifically, in step S1, the barium slag from the barium tailings is treated with hydrochloric acid to effectively remove acid-soluble inorganic salts, metal oxides, and other impurities from the barium slag; in step S2, the sparingly soluble barium compounds are converted into water-soluble barium chloride through an acidolysis reaction between hydrochloric acid and barium compounds; in step S3, ultrasonic-assisted segmented temperature control treatment is used to enhance the interaction between the impurity remover and Fe through the sonochemical and cavitation effects generated by ultrasound. 3+ Ca 2+ 、Sr 2+ The mass transfer and reaction process of impurity ions is carried out, and segmented temperature control technology is used to improve the removal efficiency and selectivity of impurity ions. In step S4, the influence of electric field on ion migration and crystal nucleation process is utilized, and the crystal form control agent is used to regulate the crystal growth direction and rate to achieve orderly growth of barium chloride crystals and effective rejection of impurity ions, and finally obtain electronic-grade barium chloride product with complete crystal structure.

[0011] Based on the above technical solution, preferably, step S1 specifically includes: crushing and screening the barium slag from the barium tailings of the toxic barium ore, then slurrying it with an ethanol-water solution, adding hydrochloric acid to the slurry for washing the slag for 0.8-1.2 hours, the liquid-solid ratio of hydrochloric acid to the barium tailings of the toxic barium ore being 1:1.8-2.2, and the concentration of hydrochloric acid being 1-1.2 mol / L, to obtain barium-containing filter residue.

[0012] Based on the above technical solutions, preferably, in step S2, the solid-liquid ratio of barium filter residue and hydrochloric acid is 1:6~8, the concentration of hydrochloric acid is 1.8~2.2mol / L, the leaching treatment temperature is 65~75℃, and the time is 1.8~2.2h.

[0013] Based on the above technical solutions, preferably, in step S3, the amount of impurity removal agent added is 2.5~3.5% of the crude barium chloride mass.

[0014] Based on the above technical solutions, preferably, the impurity removal agent includes disodium ethylenediaminetetraacetate and 8-hydroxyquinoline, with a mass ratio of disodium ethylenediaminetetraacetate to 8-hydroxyquinoline of 2.0~2.5:1.

[0015] Based on the above technical solutions, preferably, in step S3, the ultrasonic-assisted segmented temperature control treatment specifically includes: ultrasonic frequency 20~40kHz, first heating to 35~45℃, ultrasonic treatment for 10~15min, then heating to 45~55℃, ultrasonic treatment for 15~20min, and finally heating to 60~65℃, ultrasonic treatment for 6~10min.

[0016] Specifically, using EDTA on Fe 3+ Ca 2+ The strong complexing ability of polyvalent metal ions and the selective chelating properties of 8-hydroxyquinoline for transition metal ions enable synergistic complexation removal of different types of impurity ions. Combined with an ultrasonic-assisted segmented temperature-controlled treatment process, treatment at 35-45℃ for 10-15 min at an ultrasonic frequency of 20-40 kHz primarily complexes Fe. 3+ Ions, deep complexation of Ca at 45-55℃ for 15-20 min 2+ and Sr 2+ The residual impurity ions are completely complexed by treating them at 60~65℃ for 6~10 min. The mass transfer contact between the complexing agent molecules and the impurity ions is enhanced by the cavitation effect and sonochemical effect generated by ultrasound. At the same time, the graded selective removal of impurity ions is achieved by utilizing the change law of the complexation constant of different metal ions with temperature during the segmented heating process. The two technologies produce a significant synergistic effect, which greatly improves the impurity removal efficiency and selectivity while reducing the amount of impurity removal agent used.

[0017] Based on the above technical solutions, preferably, in step S4, the amount of crystal form control agent added is 0.8~1.2% of the mass of barium chloride, and the crystal form control agent includes tetra-n-butylacetic acid ammonium and sodium citrate.

[0018] Based on the above technical solutions, preferably, the mass ratio of tetrabutylammonium acetate to sodium citrate is 1.5~2.0:1.

[0019] Based on the above technical solutions, preferably, the parameters for the low-intensity DC electric field treatment are: electric field strength of 60~80 V / cm and current density of 0.1~0.3 A / m. 2 The programmed cooling rate is 0.4~0.6℃ / min, the initial crystallization temperature is 75~85℃, and the final crystallization temperature is 20~30℃.

[0020] Specifically, through the electric field on Ba 2+ and Cl ~The directional regulation of ion migration behavior, combined with programmed cooling, achieves dynamic balance optimization between nucleation and growth rates during barium chloride crystallization, while also exhibiting a selective repulsion effect on impurity ions. The crystal form control agent and electric field treatment produce a significant synergistic effect, effectively reducing the encapsulation of impurity ions and minimizing their co-crystallization behavior. Furthermore, the ordered ion migration promoted by the electric field provides a more uniform and stable reaction environment for the crystal form control agent. The synergistic effect of both ensures the final acquisition of electronically grade barium chloride with a complete crystal structure.

[0021] The present invention also provides an electronic-grade barium chloride, which is prepared by the purification method described above.

[0022] The purification method for electronic-grade barium chloride of the present invention has the following advantages over the prior art:

[0023] (1) This invention constructs a complete purification process route from barium slag in barium tailings of toxic barium chloride to electronic grade barium chloride, and combines key technologies such as hydrochloric acid graded washing and leaching, compound impurity removal agent combined with ultrasonic-assisted segmented temperature control treatment, and crystal form control agent combined with low-intensity DC electric field programmed cooling crystallization, to achieve efficient removal of impurity ions, and finally prepares electronic grade barium chloride products with impurity content lower than the electronic grade standard requirements and regular crystal morphology;

[0024] (2) By using EDTA and 8-hydroxyquinoline in combination, the broad-spectrum complexing ability of EDTA for multivalent metal ions and the selective chelating properties of 8-hydroxyquinoline for transition metal ions are brought into play, thus achieving synergistic complexing removal of different types of impurity ions. Compared with the use of a single impurity remover, the combination system has higher impurity removal efficiency and better selectivity, effectively solving the technical problems of large amount of impurity remover and poor selectivity in traditional impurity removal methods.

[0025] (3) By using tetrabutylammonium acetate and sodium citrate as a crystal form control agent, combined with a low-intensity DC electric field and a programmed cooling crystallization process, the orderly growth of barium chloride crystals and the effective rejection of impurity ions were achieved. The crystal form control agent not only regulates crystal growth but also reduces the encapsulation phenomenon of impurity ions. The electric field promotes the orderly nucleation of ions and the selective rejection of impurity ions. The programmed cooling process enables impurity ions to be effectively discharged from the crystal lattice. The synergistic effect of the three factors resulted in electronic-grade barium chloride products with complete crystal structure, solving the technical problem of unstable crystal quality in traditional crystallization methods. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of the purification method for electronic-grade barium chloride according to the present invention;

[0028] Figure 2 This is a product diagram of electronic-grade barium chloride according to the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] like Figure 1 As shown, this embodiment provides a method for purifying electronic-grade barium chloride, including the following steps:

[0032] S1. 500g of barium residue from the barium tailings of the toxic ore was crushed and screened, and then slurried with an ethanol-water solution with a volume ratio of 3:7. Hydrochloric acid was added to the slurry for washing the residue for 1.0h. The liquid-solid ratio of hydrochloric acid to barium residue from the barium tailings of the toxic ore was 1:2.0, and the concentration of hydrochloric acid was 1.1mol / L. The temperature was maintained at 30℃ and the mixture was continuously stirred during the washing process. The residue containing barium was obtained by filtration.

[0033] S2. After washing 500g of barium-containing filter residue to neutral, mix it with hydrochloric acid for leaching treatment. The solid-liquid ratio of barium-containing filter residue to hydrochloric acid is 1:7, the concentration of hydrochloric acid is 2.0mol / L, the leaching temperature is 70℃, and the time is 2.0h. Stir continuously during the leaching process. After the reaction is completed, filter while hot, and cool the filtrate to crystallize and obtain crude barium chloride.

[0034] S3. Disperse 500g of crude barium chloride in water to prepare a solution with a mass concentration of 18%. Adjust the pH of the solution to 6.0-6.5 with dilute hydrochloric acid. Add 15g of impurity removal agent, which consists of disodium ethylenediaminetetraacetate and 8-hydroxyquinoline in a mass ratio of 2.3:1. Perform segmented temperature control treatment with ultrasonic assistance. The ultrasonic frequency is 30kHz. First, raise the temperature to 40℃ and sonicate for 13min. Then raise the temperature to 50℃ and sonicate for 18min. Finally, raise the temperature to 63℃ and sonicate for 8min. After the reaction is completed, let it stand for 30min to settle. Filter to remove the complex precipitate to obtain barium chloride solution.

[0035] S4. Add 5g of crystal form control agent (ammonium tetrabutylacetate and sodium citrate in a mass ratio of 1.8:1) to the barium chloride solution. After thorough stirring and dissolution, perform programmed cooling crystallization under a low-intensity DC electric field. The electric field strength is 70 V / cm, and the current density is 0.2 A / m. 2 The cooling rate was 0.5℃ / min, the initial crystallization temperature was 80℃, and the final crystallization temperature was 25℃. After crystallization, the electric field was turned off, and aging continued at 25℃ for 3 hours. Then, barium chloride crystals were separated by filtration. The crystals were washed 2-3 times with small amounts of deionized water and anhydrous ethanol to remove surface impurities and crystal form control agents. Finally, they were vacuum dried to obtain electronic-grade barium chloride product. Figure 2 As shown.

[0036] Example 2

[0037] This embodiment provides a method for purifying electronic-grade barium chloride, including the following steps:

[0038] S1. 500g of barium residue from the barium tailings of the toxic ore was crushed and screened, and then slurried with an ethanol-water solution with a volume ratio of 3:7. Hydrochloric acid was added to the slurry for washing the residue for 1.2h. The liquid-solid ratio of hydrochloric acid to barium residue from the barium tailings of the toxic ore was 1:1.8, and the concentration of hydrochloric acid was 1mol / L. The temperature was maintained at 25℃ and the mixture was continuously stirred during the washing process. The residue containing barium was obtained by filtration.

[0039] S2. After washing 500g of barium-containing filter residue to neutrality, mix it with hydrochloric acid for leaching treatment. The solid-liquid ratio of barium-containing filter residue to hydrochloric acid is 1:6, the concentration of hydrochloric acid is 1.8mol / L, the leaching temperature is 65℃, and the time is 2.2h. Stirring is carried out continuously during the leaching process. After the reaction is completed, filter while hot, and cool the filtrate to crystallize and obtain crude barium chloride.

[0040] S3. Disperse 500g of crude barium chloride in water to prepare a 15% (w / w) solution. Adjust the pH of the solution to 6.0-6.5 with dilute hydrochloric acid. Add 12.5g of impurity remover, which consists of disodium ethylenediaminetetraacetate and 8-hydroxyquinoline in a 2:1 (w / w) ratio. Perform segmented temperature-controlled ultrasonic treatment with an ultrasonic frequency of 20kHz. First, raise the temperature to 35℃ and ultrasonically treat for 15min. Then, raise the temperature to 45℃ and ultrasonically treat for 20min. Finally, raise the temperature to 60℃ and ultrasonically treat for 10min. After the reaction is complete, allow the solution to stand for 30min to settle. Filter to remove the complex precipitate to obtain a barium chloride solution.

[0041] S4. Add 4g of crystal form control agent to the barium chloride solution. The crystal form control agent is tetrabutylammonium tetrabutylacetate and sodium citrate in a mass ratio of 1.5:1. After thorough stirring and dissolution, perform programmed cooling crystallization under a low-intensity DC electric field. The electric field strength is 60 V / cm, and the current density is 0.1 A / m. 2 The cooling rate was 0.4℃ / min, the initial crystallization temperature was 75℃, and the final crystallization temperature was 20℃. After crystallization, the electric field was turned off, and the crystals were aged at 20℃ for 4 hours. Then, the barium chloride crystals were separated by filtration. The crystals were washed 2-3 times with a small amount of deionized water and anhydrous ethanol to remove residual impurities and crystal form control agents on the surface. Finally, the crystals were vacuum dried to obtain electronic grade barium chloride product.

[0042] Example 3

[0043] This embodiment provides a method for purifying electronic-grade barium chloride, including the following steps:

[0044] S1. 500g of barium residue from the barium tailings of the toxic ore was crushed and screened, and then slurried with an ethanol-water solution with a volume ratio of 3:7. Hydrochloric acid was added to the slurry for 0.8h of washing treatment. The liquid-solid ratio of hydrochloric acid to barium residue from the barium tailings of the toxic ore was 1:2.2, and the concentration of hydrochloric acid was 1.2mol / L. The temperature was maintained at 35℃ and the mixture was continuously stirred during the washing process. The barium-containing filter residue was obtained by filtration.

[0045] S2. After washing 500g of barium-containing filter residue to neutrality, mix it with hydrochloric acid for leaching treatment. The solid-liquid ratio of barium-containing filter residue to hydrochloric acid is 1:8, the concentration of hydrochloric acid is 2.2mol / L, the leaching temperature is 75℃, and the time is 1.8h. Stirring is carried out continuously during the leaching process. After the reaction is completed, filter while hot, and cool the filtrate to crystallize and obtain crude barium chloride.

[0046] S3. Disperse 500g of crude barium chloride in water to prepare a 20% (w / w) solution. Adjust the pH of the solution to 6.0-6.5 with dilute hydrochloric acid. Add 17.5g of impurity remover, which consists of disodium ethylenediaminetetraacetate and 8-hydroxyquinoline in a (w / w) ratio of 2.5:1. Perform segmented temperature-controlled ultrasonic treatment with an ultrasonic frequency of 40kHz. First, raise the temperature to 45℃ and ultrasonically treat for 10min. Then, raise the temperature to 55℃ and ultrasonically treat for 15min. Finally, raise the temperature to 65℃ and ultrasonically treat for 6min. After the reaction is complete, allow the solution to stand for 30min to settle. Filter to remove the complex precipitate to obtain a barium chloride solution.

[0047] S4. Add 6g of crystal form control agent (ammonium tetrabutylacetate and sodium citrate in a mass ratio of 2.0:1) to the barium chloride solution. After thorough stirring and dissolution, perform programmed cooling crystallization under a low-intensity DC electric field. The electric field strength is 80 V / cm, and the current density is 0.3 A / m. 2 The cooling rate was 0.6℃ / min, the initial crystallization temperature was 85℃, and the final crystallization temperature was 30℃. After crystallization, the electric field was turned off, and the crystals were aged at 30℃ for 2 hours. Then, the barium chloride crystals were separated by filtration. The crystals were washed 2-3 times with a small amount of deionized water and anhydrous ethanol to remove residual impurities and crystal form control agents on the surface. Finally, the crystals were vacuum dried to obtain electronic grade barium chloride product.

[0048] Comparative Example 1

[0049] This comparative example provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0050] S1 and S2 are the same as in Example 1.

[0051] S3. Disperse 500g of crude barium chloride in water to prepare a solution with a mass concentration of 18%. Adjust the pH of the solution to 6.0-6.5 with dilute hydrochloric acid. Add 15g of impurity removal agent, which consists of disodium ethylenediaminetetraacetate and 8-hydroxyquinoline in a mass ratio of 2.3:1. Sonicate the solution at a frequency of 30kHz and a temperature of 50℃ for 39 minutes. After the reaction is complete, allow the solution to stand and settle for 30 minutes. Filter to remove the complex precipitate to obtain a barium chloride solution.

[0052] S4 is the same as in Example 1.

[0053] Comparative Example 2

[0054] This comparative example provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0055] S1 and S2 are the same as in Example 1.

[0056] S3. Disperse 500g of crude barium chloride in water to prepare a solution with a mass concentration of 18%. Adjust the pH of the solution to 6.0-6.5 with dilute hydrochloric acid. Add 15g of impurity remover, which is disodium ethylenediaminetetraacetate. Perform segmented temperature control treatment with ultrasonic assistance. The ultrasonic frequency is 30kHz. Raise the temperature to 40℃ and sonicate for 13min. Then raise the temperature to 50℃ and sonicate for 18min. Finally raise the temperature to 63℃ and sonicate for 8min. After the reaction is completed, let it stand for 30min to settle. Filter to remove the complex precipitate to obtain barium chloride solution.

[0057] S4 is the same as in Example 1.

[0058] Comparative Example 3

[0059] This comparative example provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0060] S1, S2, and S3 are the same as in Example 1.

[0061] S4. Add 5g of a crystal form control agent (sodium citrate) to the barium chloride solution. After thorough stirring and dissolution, perform programmed cooling crystallization under a low-intensity DC electric field. The electric field strength is 70 V / cm, and the current density is 0.2 A / m. 2 The cooling rate was 0.5℃ / min, the initial crystallization temperature was 80℃, and the final crystallization temperature was 25℃. After crystallization, the electric field was turned off, and the crystals were aged at 25℃ for 3 hours. Then, the barium chloride crystals were separated by filtration. The crystals were washed 2-3 times with a small amount of deionized water and anhydrous ethanol to remove residual impurities and crystal form control agents on the surface. Finally, the crystals were vacuum dried to obtain electronic grade barium chloride product.

[0062] Comparative Example 4

[0063] This comparative example provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0064] S1, S2, and S3 are the same as in Example 1.

[0065] S4. Add 5g of a crystal form control agent (tetra-n-butylammonium acetate) to the barium chloride solution. After thorough stirring and dissolution, perform programmed cooling crystallization under a low-intensity DC electric field. The electric field strength is 70 V / cm, and the current density is 0.2 A / m. 2 The cooling rate was 0.5℃ / min, the initial crystallization temperature was 80℃, and the final crystallization temperature was 25℃. After crystallization, the electric field was turned off, and the crystals were aged at 25℃ for 3 hours. Then, the barium chloride crystals were separated by filtration. The crystals were washed 2-3 times with a small amount of deionized water and anhydrous ethanol to remove residual impurities and crystal form control agents on the surface. Finally, the crystals were vacuum dried to obtain electronic grade barium chloride product.

[0066] Comparative Example 5

[0067] This comparative example provides a method for purifying electronic-grade barium chloride, comprising the following steps:

[0068] S1, S2, and S3 are the same as in Example 1.

[0069] S4. Add 5g of crystal form control agent to the barium chloride solution. The crystal form control agent is tetrabutylammonium acetate and sodium citrate in a mass ratio of 1.8:1. After stirring and dissolving thoroughly, evaporate and crystallize. Aging at 25℃ for 3 hours, then filter to separate the barium chloride crystals. Wash the crystals 2-3 times with a small amount of deionized water and anhydrous ethanol to remove residual impurities and crystal form control agent from the surface. Finally, vacuum dry to obtain electronic grade barium chloride product.

[0070] Performance testing

[0071] The electronic-grade barium chloride products prepared in the examples and comparative examples were subjected to quality testing. The testing indicators included purity and impurity content, where the impurity content included Fe, Ca, Sr, Mg, heavy metals (calculated as Pb), and Al. The test results are shown in Table 1.

[0072] Table 1 Comparison of Product Quality

[0073]

[0074] As shown in Table 1, the electronic-grade barium chloride product prepared by the technical solution of this invention has low impurity content and high purity, meeting the standards for electronic-grade barium chloride. However, the quality of the barium chloride products in Comparative Examples 1-5 is inferior to that of Example 1. The reasons for this are as follows: Comparative Example 1 uses isothermal ultrasonic treatment. At a single temperature, EDTA and 8-hydroxyquinoline exhibit strong competition for complexing various impurity ions, leading to a slight decrease in impurity removal efficiency and selectivity. Comparative Example 2 uses only EDTA as a single impurity remover, lacking the synergistic effect of 8-hydroxyquinoline. Although EDTA has a broad-spectrum complexing ability for multivalent metal ions, its selectivity for transition metal ions is relatively weak, resulting in a significant decrease in iron removal efficiency and a corresponding increase in the residual amounts of metals such as calcium and strontium. Comparative Example 3 lacks the surface activity regulation effect of tetra-n-butylacetic acid, leading to an increase in the inclusion of impurity ions during crystallization, resulting in a relatively high residual amount of metals such as strontium in the final product. Comparative Example 4 uses only tetra-n-butylacetic acid as a single crystal form control agent, and its product quality is also lower than that of Example 1. Comparative Example 5 uses evaporation crystallization instead of electric field-programmed cooling crystallization. During the evaporation crystallization process, the rapid solvent evaporation leads to an excessively fast crystallization rate. The inclusion of impurity ions and co-crystallization during the crystallization process result in a decrease in the quality of the final product.

[0075] 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 within the protection scope of the present invention.

Claims

1. A method for purifying electronic-grade barium chloride, characterized by, The method comprises the following steps: S1, obtaining barium-containing filter residue by washing the barium residue of wickenite tailings with hydrochloric acid; S2, mixing the barium-containing filter residue and hydrochloric acid for leaching treatment to obtain crude barium chloride; S3, dispersing the crude barium chloride in water, adjusting the pH of the solution, adding a decontaminating agent, and performing ultrasonic-assisted stepwise temperature control treatment to obtain a barium chloride solution after filtration; the decontaminating agent comprises disodium ethylenediaminetetraacetate and 8-hydroxyquinoline, and the mass ratio of disodium ethylenediaminetetraacetate to 8-hydroxyquinoline is 2.0-2.5:1; S4, adding a crystal form control agent to the barium chloride solution, and performing programmed cooling crystallization under the action of a low-intensity direct current electric field to obtain electronic-grade barium chloride; the crystal form control agent comprises tetra-n-butylammonium acetate and sodium citrate; In step S3, the ultrasonic-assisted stepwise temperature control treatment specifically comprises: first, ultrasonic frequency of 20-40 kHz, heating to 35-45 DEG C, ultrasonic treatment for 10-15 min, then heating to 45-55 DEG C, ultrasonic treatment for 15-20 min, and finally heating to 60-65 DEG C, ultrasonic treatment for 6-10 min.

2. A method of purification of electronic grade barium chloride as claimed in claim 1, wherein: Step S1 specifically comprises: crushing and screening the barium residue of wickenite tailings, then performing pulp treatment with an ethanol-water solution, adding hydrochloric acid to the slurry for 0.8-1.2 h of washing residue treatment, the liquid-solid ratio of hydrochloric acid to barium residue of wickenite tailings is 1:1.8-2.2, the concentration of hydrochloric acid is 1-1.2 mol / L, and barium-containing filter residue is obtained.

3. A method of purifying electronic grade barium chloride as claimed in claim 1, wherein: In step S2, the solid-liquid ratio of the barium-containing filter residue to hydrochloric acid is 1:6-8, the concentration of hydrochloric acid is 1.8-2.2 mol / L, the leaching treatment temperature is 65-75 DEG C, and the leaching treatment time is 1.8-2.2 h.

4. A method of purifying electronic grade barium chloride as claimed in claim 1, wherein: In step S3, the amount of the decontaminating agent added is 2.5-3.5% of the mass of the crude barium chloride.

5. A process for purification of electronic grade barium chloride as claimed in claim 1 wherein: In step S4, the amount of the crystal form control agent added is 0.8-1.2% of the mass of the crude barium chloride.

6. A process for purification of electronic grade barium chloride as claimed in claim 1 wherein: The mass ratio of tetra-n-butylammonium acetate to sodium citrate is 1.5-2.0:

1.

7. A process for purification of electronic grade barium chloride as claimed in claim 1 wherein: The parameter of the low-intensity direct current electric field treatment is that the electric field intensity is 60-80 V / cm, the current density is 0.1-0.3 A / m 2 The program cooling rate is 0.4-0.6 DEG C / min, the initial crystallization temperature is 75-85 DEG C, and the terminal crystallization temperature is 20-30 DEG C.

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