Industrial-grade barium carbonate and production method thereof

Abstract

The present invention provides an industrial-grade barium carbonate and a production method thereof, relating to the technical field of barium carbonate production. The method comprises the following steps: S1. After pre-treating crude barium sulfide, hot filtration is performed under inert gas protection, followed by reduced pressure concentration, and cooling to obtain a barium sulfide concentrate; S2. The barium sulfide concentrate is adjusted to alkalinity, and an antioxidant and a hydrolysis inhibitor are added thereto while stirring. The solution is filtered through a PVDF membrane to obtain a barium sulfide solution; S3. Under inert gas protection, carbon dioxide is introduced into the barium sulfide solution, followed by desulfurization and washing, vacuum filtration, drying and pulverization to obtain barium carbonate. The industrial-grade barium carbonate of the present invention has a purity of not less than 99.9%, a chloride ion content of not more than 8 ppm, a sulfide content of less than 50 ppm, a sulfate content of less than 0.03%, a sulfite content of less than 0.05%, and an iron ion content of less than 5 ppm.

Description

Technical Field

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

[0002] Barium carbonate (BaCO3) is an important inorganic chemical product, widely used in electronic ceramics, optical glass, magnetic materials, flame retardants, and the production of other barium salts. The main methods for industrial production of barium carbonate include double decomposition (reaction of barium chloride with carbonates) and carbonization (reaction of barium sulfide with carbon dioxide). Carbonization has become the mainstream process for producing barium carbonate due to its readily available raw materials and low cost.

[0003] However, the traditional carbonization method still has some limitations when producing barium carbonate, especially in controlling product purity. This method mainly produces barium carbonate through the reaction of barium sulfide and carbon dioxide. However, in actual operation, it is difficult to avoid the introduction of impurities such as sulfate, iron ions, and chloride ions. These impurities seriously affect the purity and application performance of the product.

[0004] Therefore, there is an urgent need to develop a new method for producing industrial-grade barium carbonate to obtain barium carbonate products with higher purity to meet the demand of the high-end market for high-purity barium carbonate. Summary of the Invention

[0005] In view of this, the present invention proposes a method for efficiently producing high-purity barium carbonate to reduce the content of impurities in the final product as much as possible.

[0006] In a first aspect, the present invention provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0007] S1. After pre-treating the crude barium sulfide, the crude barium sulfide is filtered hot under an inert gas atmosphere, and then concentrated under reduced pressure and cooled to obtain a barium sulfide concentrate;

[0008] S2, adjusting the barium sulfide concentrated solution of step S1 to alkaline, adding an antioxidant and a hydrolysis inhibitor thereto under stirring, and filtering through a PVDF membrane to obtain a barium sulfide solution;

[0009] S3. Under the protection of inert gas, carbon dioxide is introduced into the barium sulfide solution of step S2, followed by desulfurization and washing, vacuum filtration, drying and crushing to obtain barium carbonate.

[0010] In one or some possible embodiments, in step S1, the temperature of the hot filtration is 60-70° C., and the pressure is 0.05-1 MPa.

[0011] In one or some possible embodiments, in step S1, the pressure of the reduced pressure concentration is -0.08 to -0.1 MPa, and the concentration of the barium sulfide concentrate is 20 to 22%;

[0012] The cooling method includes: cooling to 40°C at a rate of 3-4°C / min, and then cooling to 20-25°C at a rate of 0.6-1.4°C / min.

[0013] By adopting the above technical solution, localized supersaturation caused by rapid cooling can be effectively avoided, thereby preventing the precipitation of impurities. This staged and controlled cooling rate method is conducive to maintaining the uniformity and stability of the solution, resulting in a purer barium carbonate crystal structure, reducing the incorporation of impurities, and thus improving the purity and quality of the final product.

[0014] In one or some possible embodiments, in step S2, the pH value of the barium sulfide concentrate in step S1 is adjusted to 9.5-10.

[0015] The above technical solution helps stabilize the barium sulfide solution, preventing hydrolysis to produce barium hydroxide or other byproducts. This not only ensures the purity and efficiency of subsequent reactions but also avoids product quality degradation due to impurities. Furthermore, a properly alkaline environment helps antioxidants and hydrolysis inhibitors achieve optimal performance, enhancing solution stability.

[0016] In one or some possible embodiments, in step S2, the antioxidant is selected from ascorbic acid and / or disodium EDTA, and the hydrolysis inhibitor is selected from thiourea and / or sodium citrate.

[0017] By adopting this technical solution, the antioxidant effectively scavenges oxygen free radicals in the solution, preventing oxidation of the barium sulfide during the treatment process, thereby maintaining its chemical stability. Simultaneously, the hydrolysis inhibitor effectively inhibits the hydrolysis of the barium sulfide, preventing the formation of unnecessary byproducts such as barium hydroxide, and ensuring the purity of the solution.

[0018] In one or some possible embodiments, in step S2, the mass ratio of the barium sulfide concentrate, the antioxidant, and the hydrolysis inhibitor is 1000:(0.5-1.0):(0.6-1.2).

[0019] In one or some possible embodiments, in step S2, the pore size of the PVDF membrane is 0.22-0.26 μm.

[0020] By adopting the above technical solution, PVDF membrane filtration has significant advantages over conventional filtration: its precise pore size of 0.22-0.26μm can effectively intercept submicron impurities such as colloidal silicate and BaSO4 microcrystals, making Fe3+ The removal rate of metal impurities such as PVDF membrane is greater than 98%. It also has certain corrosion resistance, sulfide corrosion resistance, strong alkali resistance, and low-temperature thermal stability. It can not only meet the production temperature requirements, but also provide good flux and filtration efficiency, ensuring the smoothness and economy of the production process, and is suitable for the needs of large-scale industrial production. Actual operation data shows that the liquid NTU value after PVDF membrane filtration does not exceed 9, Fe 3+ Residue <10ppm, single membrane processing capacity reaches 500-800m 3 Chemical cleaning can restore over 95% of the flux, with a service life of up to three months. The overall cost is lower than that of frequently replaced conventional filter media. The use of this membrane not only ensures that the main components of the barium sulfide solution are not lost, but also further improves the purity of the solution, reduces the impurity content in the final barium carbonate product, and improves the purity and quality of the product.

[0021] In one or some possible embodiments, in step S3, the carbon dioxide is introduced at a rate of 0.3-0.5 L / min until the pH of the mixed solution is 8-8.5; and then at a rate of 1.5-1.8 L / min until the pH of the mixed solution is 6.5-7.

[0022] By adopting this technical solution, a relatively low rate of carbon dioxide introduction in the initial stage helps to gently initiate the reaction, avoiding localized overcarbonization caused by rapid acidification and the formation of Ba(HCO3)2. BaCO3 crystal nuclei are generated at a low rate. As the solution pH approaches the target range, increasing the carbon dioxide introduction rate can accelerate the reaction process, ensure sufficient carbonization, and stabilize the final pH value within the ideal range, which is conducive to obtaining a high-purity barium carbonate product.

[0023] In one or some possible embodiments, in step S3, the desulfurizing agent is selected from O3 with a volume fraction of 8-12%; the O3 and S 2- The molar ratio is 1.2~1.5:1.

[0024] By adopting this technical solution, sufficient oxidation capacity is ensured to completely remove sulfides, while avoiding the waste of resources and possible side reactions caused by excessive use of ozone. This not only improves the purity of the final barium carbonate product and reduces impurity content, but also reduces production costs and improves environmental friendliness through optimized desulfurization conditions.

[0025] In one or some possible embodiments, in step S3, the washing method includes: first washing with deionized water until the conductivity of the filtrate does not exceed 50 μS / cm, and then washing with 0.5% dilute ammonia water and 60-70% ethanol in sequence.

[0026] By adopting this technical solution, firstly, the majority of water-soluble impurities and residual electrolytes can be effectively removed, ensuring the high purity of the barium carbonate product. Secondly, it helps further remove surface-adsorbed impurities, improving the chemical stability and purity of the product. Finally, it not only efficiently removes organic impurities and moisture, but also promotes rapid drying and reduces particle agglomeration.

[0027] In a second aspect, the present invention relates to industrial-grade barium carbonate prepared by the above method.

[0028] The industrial-grade barium carbonate and its production method provided by the present invention have the following beneficial effects compared with the prior art:

[0029] (1) The industrial-grade barium carbonate of the present invention has a purity of not less than 99.9%, a chloride ion content of not more than 8 ppm, a sulfide content of less than 50 ppm, a sulfate content of less than 0.03%, a sulfite content of less than 0.05%, and an iron ion content of less than 5 ppm.

[0030] (2) The method for producing industrial-grade barium carbonate of the present invention is simple to operate and easy to control. It not only effectively reduces the impurity content, but also ensures the stability of production and the consistency of products, which is conducive to improving production efficiency and reducing production costs. It is suitable for large-scale production of industrial-grade barium carbonate. 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] There are three main problems in the existing carbonization method for producing barium carbonate: first, the raw material barite is not fully reduced, resulting in a low conversion rate of barium sulfide (usually only 85%-90%); second, during the carbonization process, the industrial barium sulfide solution often contains residual by-products, such as FeS, which are easily reacted with CO3 during the carbonization process. 2- Co-precipitation or inclusion formation occurs, introducing impurities such as Fe into the final product; thirdly, the product purity is limited to the purity of industrial carbon dioxide (usually 99.5%).

[0033] The method for preparing industrial-grade barium carbonate provided by the present invention can fundamentally improve the purity of the reactant barium sulfide. During the preparation process, first, through a series of fine control steps, including pretreatment, hot filtration and reduced pressure concentration under inert gas protection, precise adjustment of pH value and addition of antioxidants and hydrolysis inhibitors, and finally using PVDF membrane for precision filtration and other process measures, impurities and insoluble matter in the barium sulfide solution can be effectively removed to ensure its high purity and high stability. These measures not only significantly reduce the content of impurities such as thiosulfate, chloride ions, and metal ions in barium sulfide, but also greatly improve the overall purity of the barium sulfide solution. Secondly, by precisely controlling the carbon dioxide introduction rate and adopting efficient desulfurization and washing technology, the generated barium carbonate has extremely high purity and low impurity levels. The purity of the barium sulfide solution prepared by the method of the present invention can be as high as 99.85% or more, and the purity of the barium carbonate product finally obtained is not less than 99.90%, and the content of key impurities such as chloride ions, sulfides, sulfates, sulfites and iron ions is maintained at a very low level.

[0034] The technical solution of the present invention will now be further described with reference to specific embodiments.

[0035] In the present invention, crude barium sulfide can be prepared by reacting barium salt and sulfide, can be prepared by thermal reduction of barite, can be extracted from barium-containing fertilizer waste, or can be directly obtained from the market.

[0036] In the present invention, the pretreatment of crude barium sulfide includes sequentially acid washing, water washing, and crushing. The acid washing step is intended to remove oxide impurities on the surface of the barium sulfide to ensure purity for subsequent reactions. The water washing is used to neutralize the barium sulfide product to eliminate the impact of residual acidic substances after acid washing on subsequent processes. Finally, crushing increases the dissolution contact area of ​​the barium sulfide, thereby improving its dispersibility and reactivity in the solution. The specific materials and methods used in this process are not strictly limited; as long as the above objectives are achieved, the appropriate operation method can be flexibly selected. In the present embodiment, the inventors preferred pretreatment method: first, wash the barium sulfide solid with 5% hydrochloric acid to remove surface oxides and dissolve alkaline impurities (such as Na2S and K2S), then rinse with deionized water until the wash water is neutral (pH 6-7), and finally, crush and sieve to obtain barium sulfide powder with a particle size of 80-100 mesh.

[0037] In the present invention, the PVDF membrane needs to be pre-washed with 95% ethanol and aged under hydrothermal conditions at 60°C.

[0038] Example 1

[0039] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0040] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 60°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 0.06 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.08 MPa. The mixture was cooled to 40°C at a rate of 3°C / min, kept at a constant temperature for 15 minutes, and then cooled to 25°C at a rate of 0.8°C / min to obtain a barium sulfide concentrate with a concentration of 20%.

[0041] S2, using 10% sodium hydroxide solution to adjust the pH value of the barium sulfide concentrate in step S1 to 9.5, under stirring, disodium EDTA accounting for 0.05% of the barium sulfide concentrate (i.e., adding 0.5 kg per 1000 kg of the concentrate, the same as the following embodiments and comparative examples, no further explanation is given), and thiourea accounting for 0.1% of the barium sulfide concentrate (i.e., adding 1.0 kg per 1000 kg, the same as the following embodiments and comparative examples, no further explanation is given) are dissolved in 60° C. hot water, and after complete dissolution, the mixture is added to the barium sulfide concentrate, and filtered through a 0.26 μm PVDF membrane to obtain a barium sulfide solution;

[0042] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.82%, the water-insoluble matter was not more than 1 ppm, the chloride ion content was not more than 38 ppm, the thiosulfate content was about 0.07%, and the Fe 3+ / Ca 2+ The metal ion content is less than 10ppm, and the NTU is less than 8.2.

[0043] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.3 L / min until the pH of the mixed solution was 8, and then CO2 was introduced at a rate of 1.5 L / min until the pH of the mixed solution was 6.5, and then S 2- The product was desulfurized by using ozone with a molar ratio of 1.4 times and a volume fraction of 8%, and then washed with deionized water until the conductivity of the filtrate did not exceed 50 μS / cm. The product was then washed with 0.5% dilute ammonia water and 70% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0044] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.92%, the chloride ion content did not exceed 8 ppm, the sulfide content was approximately 13 ppm, the sulfate content was approximately 0.018%, the sulfite content was approximately 0.0027%, and the iron ion content was approximately 3 ppm.

[0045] Example 2

[0046] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0047] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 70°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 1 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.1 MPa. The mixture was cooled to 35°C at a rate of 5°C / min, kept at a constant temperature for 15 minutes, and then cooled to 20°C at a rate of 1°C / min to obtain a barium sulfide concentrate with a concentration of 22%.

[0048] S2, using 10% sodium hydroxide solution to adjust the pH value of the barium sulfide concentrate in step S1 to 10, and adding 0.1% ascorbic acid solution and 0.6% thiourea solution to the barium sulfide concentrate in sequence under stirring, and filtering through a 0.22 μm PVDF membrane to obtain a barium sulfide solution;

[0049] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.85%, the water-insoluble matter was not more than 1 ppm, the chloride ion content was not more than 40 ppm, the thiosulfate content was about 0.07%, and the Fe 3+ / Ca 2+ The metal ion content is less than 10ppm, and the NTU is less than 8.5.

[0050] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.5 L / min until the pH of the mixed solution was 8.5, and then CO2 was introduced at a rate of 1.8 L / min until the pH of the mixed solution was 7, and then S 2- Desulfurization is carried out with ozone at a molar ratio of 1.5 times and a volume fraction of 12%, and then the filtrate is washed with deionized water until the conductivity of the filtrate does not exceed 50μS / cm. The filtrate is then washed with 0.5% dilute ammonia water and 60% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0051] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.92%, the chloride ion content did not exceed 8 ppm, the sulfide content was approximately 15 ppm, the sulfate content was approximately 0.020%, the sulfite content was approximately 0.003%, and the iron ion content was approximately 4 ppm.

[0052] Example 3

[0053] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0054] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 65°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 1 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.1 MPa. The mixture was cooled to 35°C at a rate of 5°C / min, kept at a constant temperature for 15 minutes, and then cooled to 20°C at a rate of 1°C / min to obtain a barium sulfide concentrate with a concentration of 21%.

[0055] S2. The barium sulfide concentrate of step S1 was adjusted to a pH of 10 using a 10% sodium hydroxide solution. 0.1% disodium EDTA solution and 0.6% thiourea solution were sequentially added to the barium sulfide concentrate under stirring, and the mixture was filtered through a 0.22 μm PVDF membrane to obtain a barium sulfide solution.

[0056] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.83%, the water-insoluble matter was not more than 1 ppm, the chloride ion content was not more than 42 ppm, the thiosulfate content was about 0.075%, and the Fe 3+ / Ca 2+ The metal ion content is <11ppm, NTU <8.7.

[0057] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.5 L / min until the pH of the mixed solution was 8.5, and then CO2 was introduced at a rate of 1.8 L / min until the pH of the mixed solution was 7, and then S 2- Desulfurization is carried out with ozone having a molar ratio of 1.5 times and a volume fraction of 10%, and then the filtrate is washed with deionized water until the conductivity of the filtrate does not exceed 50 μS / cm. The filtrate is then washed with 0.5% dilute ammonia water and 60% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0058] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.91%, the chloride ion content did not exceed 8 ppm, the sulfide content was approximately 14 ppm, the sulfate content was approximately 0.019%, the sulfite content was approximately 0.0028%, and the iron ion content was approximately 3.5 ppm.

[0059] Example 4

[0060] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0061] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 65°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 0.07 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.1 MPa. The mixture was cooled to 35°C at a rate of 4°C / min, kept at a constant temperature for 15 minutes, and then cooled to 20°C at a rate of 0.7°C / min to obtain a barium sulfide concentrate with a concentration of 21%.

[0062] S2, using 10% sodium hydroxide solution to adjust the pH value of the barium sulfide concentrate in step S1 to 10, and adding 0.06% ascorbic acid solution and 0.09% sodium citrate solution to the barium sulfide concentrate in sequence under stirring, and filtering through a 0.25 μm PVDF membrane to obtain a barium sulfide solution;

[0063] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.83%, the water-insoluble matter was not more than 1 ppm, the chloride ion content was not more than 40 ppm, the thiosulfate content was about 0.07%, and the Fe 3+ / Ca 2+ The metal ion content is less than 10ppm, and the NTU is less than 8.5.

[0064] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.4 L / min until the pH of the mixed solution was 8, and then CO2 was introduced at a rate of 1.7 L / min until the pH of the mixed solution was 6.5, and then S 2- Desulfurization is carried out with ozone having a molar ratio of 1.4 times and a volume fraction of 10%, and then the filtrate is washed with deionized water until the conductivity of the filtrate does not exceed 50 μS / cm. The filtrate is then washed with 0.5% dilute ammonia water and 60% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0065] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.91%, the chloride ion content did not exceed 8 ppm, the sulfide content was approximately 14 ppm, the sulfate content was approximately 0.02%, the sulfite content was approximately 0.003%, and the iron ion content was approximately 4 ppm.

[0066] Example 5

[0067] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0068] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 65°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 0.08 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.1 MPa. The mixture was cooled to 35°C at a rate of 4°C / min, kept at a constant temperature for 15 minutes, and then cooled to 20°C at a rate of 0.8°C / min to obtain a barium sulfide concentrate with a concentration of 22%.

[0069] S2. The barium sulfide concentrate of step S1 was adjusted to a pH of 10 using a 10% sodium hydroxide solution. 0.05% disodium EDTA solution and 0.08% thiourea solution were sequentially added to the barium sulfide concentrate under stirring, and the mixture was filtered through a 0.24 μm PVDF membrane to obtain a barium sulfide solution.

[0070] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.85%, the water-insoluble matter was not more than 0.5 ppm, the chloride ion content was not more than 30 ppm, the thiosulfate content was about 0.060%, and the Fe 3+ / Ca 2+ The metal ion content is <8ppm, NTU <8.7.

[0071] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.45 L / min until the pH of the mixed solution was 8.5, and then CO2 was introduced at a rate of 1.65 L / min until the pH of the mixed solution was 6.5, and then S 2- Desulfurization is carried out with ozone having a molar ratio of 1.45 times and a volume fraction of 10%, and then the filtrate is washed with deionized water until the conductivity of the filtrate does not exceed 50 μS / cm. The filtrate is then washed with 0.5% dilute ammonia water and 60% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0072] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.95%, the chloride ion content did not exceed 5 ppm, the sulfide content was approximately 10 ppm, the sulfate content was approximately 0.015%, the sulfite content was approximately 0.002%, and the iron ion content was approximately 2 ppm.

[0073] Example 6

[0074] This embodiment provides a method for producing industrial-grade barium carbonate, comprising the following steps:

[0075] S1. After pre-treating the crude barium sulfide, the barium sulfide powder and 0.1% thiourea by mass of the barium sulfide powder were dissolved in 60°C hot water under nitrogen (purity ≥ 99.99%). The mixture was filtered while hot at a pressure of 0.06 MPa to remove insoluble impurities (such as silicates and unreacted barium sulfate). The mixture was then concentrated under reduced pressure at a pressure of -0.08 MPa. The mixture was cooled to 35°C at a rate of 3°C / min, kept at a constant temperature for 15 minutes, and then cooled to 20°C at a rate of 0.85°C / min to obtain a barium sulfide concentrate with a concentration of 18%;

[0076] S2, using 10% sodium hydroxide solution to adjust the pH value of the barium sulfide concentrate in step S1 to 10, and adding 0.07% ascorbic acid solution and 0.1% thiourea solution to the barium sulfide concentrate in sequence under stirring, and filtering through a 0.23 μm PVDF membrane to obtain a barium sulfide solution;

[0077] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.84%, the water-insoluble matter was not more than 0.8 ppm, the chloride ion content was not more than 35 ppm, the thiosulfate content was about 0.065%, and the Fe 3+ / Ca 2+ The metal ion content is <9ppm, NTU <8.3.

[0078] S3, under nitrogen atmosphere, CO2 was introduced into the barium sulfide solution of step S2 at a rate of 0.35 L / min until the pH of the mixed solution was 8, and then CO2 was introduced at a rate of 1.6 L / min until the pH of the mixed solution was 7, and then S 2- Desulfurization is carried out with ozone having a molar ratio of 1.35 times and a volume fraction of 12%, and then the filtrate is washed with deionized water until the conductivity of the filtrate does not exceed 50 μS / cm. The filtrate is then washed with 0.5% dilute ammonia water and 60% ethanol in sequence, vacuum filtered, dried and crushed to obtain barium carbonate.

[0079] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.93%, the chloride ion content did not exceed 7 ppm, the sulfide content was approximately 12 ppm, the sulfate content was approximately 0.017%, the sulfite content was approximately 0.0025%, and the iron ion content was approximately 3 ppm.

[0080] Comparative Example 1

[0081] The difference from Example 5 is that in step S2, no antioxidant is added, and the other steps remain unchanged.

[0082] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.78%, the water-insoluble matter was not more than 2ppm, the chloride ion content was not more than 45ppm, the thiosulfate content was about 0.1%, and the Fe 3+ / Ca 2+ The metal ion content is less than 12ppm.

[0083] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.88%, the chloride ion content did not exceed 12 ppm, the sulfide content was approximately 15 ppm, the sulfate content was approximately 0.022%, the sulfite content was approximately 0.0035%, and the iron ion content was approximately 5 ppm.

[0084] Comparative Example 2

[0085] The difference from Example 5 is that in step S2, no hydrolysis inhibitor is added, and the other steps remain unchanged.

[0086] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.75%, the water-insoluble matter was not more than 3 ppm, the chloride ion content was not more than 50 ppm, the thiosulfate content was about 0.12%, and the Fe 3+ / Ca 2+ The metal ion content is less than 15ppm.

[0087] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.85%, the chloride ion content did not exceed 15 ppm, the sulfide content was approximately 18 ppm, the sulfate content was approximately 0.025%, the sulfite content was approximately 0.004%, and the iron ion content was approximately 6 ppm.

[0088] Comparative Example 3

[0089] The difference from Example 5 is that in step S2, no antioxidant and hydrolysis inhibitor are added, and the other steps remain unchanged.

[0090] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.70%, the water-insoluble matter was not more than 4 ppm, the chloride ion content was not more than 60 ppm, the thiosulfate content was about 0.15%, and the Fe 3+ / Ca 2+ The metal ion content is less than 20ppm.

[0091] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.80%, the chloride ion content did not exceed 20 ppm, the sulfide content was approximately 20 ppm, the sulfate content was approximately 0.03%, the sulfite content was approximately 0.005%, and the iron ion content was approximately 8 ppm.

[0092] Combining Example 5 with Comparative Examples 1-3, it can be seen that, taking thiosulfate in the barium sulfide solution as an example, the thiosulfate content in the barium sulfide solution of Example 5 was approximately 0.060%. In Comparative Example 1, no antioxidant was added, and the thiosulfate content in the barium sulfide solution increased to approximately 0.1%, an increase of 0.04%, or approximately 67%, compared to Example 5. In Comparative Example 2, no hydrolysis inhibitor was added, and the thiosulfate content in the barium sulfide solution increased to approximately 0.12%, an increase of 100% compared to Example 5. In Comparative Example 3, neither an antioxidant nor a hydrolysis inhibitor was added, and the thiosulfate content in the barium sulfide solution increased to approximately 0.15%, an increase of approximately 0.09%, or 150%, compared to Example 5. In addition, in the final barium carbonate product, the chloride ion content in Example 5 is also much lower than that in Comparative Examples 1 to 3. This is because the antioxidant blocks the co-precipitation and catalytic oxidation of metal ions and chloride ions, and the hydrolysis inhibitor reduces the formation of thiosulfate, preventing it from forming a stable complex with chloride ions, thereby achieving the effect of jointly reducing the chloride ion content.

[0093] This shows that the antioxidant and hydrolysis inhibitor selected in the present invention can effectively inhibit the formation of by-products, which is of great significance in improving product purity and reducing impurity content.

[0094] Based on the above examples, the inventors took Example 5 as an example to further analyze the effects of the dosage of antioxidants and hydrolysis inhibitors on the barium sulfide solution. The results are shown in Table 1.

[0095] Table 1 Additive dosage and effect analysis

[0096]

[0097] As shown in Table 1, in Comparative Example 4, due to the reduction in the amount of antioxidant and hydrolysis inhibitor, the oxidation reaction in the system is aggravated and the hydrolysis reaction fails to be effectively controlled, which makes the by-product thiosulfate significantly increase, and the chloride ion content also rises significantly because the impurity removal efficiency decreases. In Comparative Example 5, excessive antioxidant and hydrolysis inhibitor are used, but the content of thiosulfate and chloride ion is similar to Example 5, indicating that excessive use of additives does not bring better results, but can lead to an increase in production cost, and even continuing to expand the amount can also cause unnecessary side reactions. From the perspective of Comprehensive Comparative Examples 6 to 9, antioxidants can improve the overall impurity control effect, and the amount of hydrolysis inhibitor is directly related to the amount of by-products generated. Single increase or decrease in the amount of antioxidant or hydrolysis inhibitor may cause impurities to increase, thereby affecting product quality.

[0098] Comparative Example 10

[0099] The difference from Example 5 is that in step S2, PVDF membrane filtration is not performed, and the other steps remain unchanged.

[0100] The barium sulfide solution prepared in step S2 was tested. The purity of the barium sulfide solution was not less than 99.80%, the water-insoluble matter was not more than 5ppm, the chloride ion content was not more than 55ppm, the thiosulfate content was about 0.11%, and the Fe 3+ / Ca 2+ The metal ion content is less than 18ppm.

[0101] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.85%, the chloride ion content did not exceed 18 ppm, the sulfide content was approximately 16 ppm, the sulfate content was approximately 0.023%, the sulfite content was approximately 0.0038%, and the iron ion content was approximately 7 ppm.

[0102] Comparative Example 11

[0103] The difference from Example 5 is that in step S3, CO2 is introduced at a rate of 1.0 L / min until the pH of the mixed solution reaches 6.5, and the other steps remain unchanged.

[0104] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity was not less than 99.90%, the chloride ion content did not exceed 10 ppm, the sulfide content was approximately 14 ppm, the sulfate content was approximately 0.019%, the sulfite content was approximately 0.0032%, and the iron ion content was approximately 4 ppm.

[0105] Comparative Example 12

[0106] The difference from Example 5 is that in step S3, no desulfurization treatment is performed.

[0107] The product was tested according to the relevant testing standards for industrial barium carbonate (GB / T 1614-2021). The results showed that the barium carbonate purity did not exceed 99.80%, the chloride ion content did not exceed 10 ppm, the sulfide content was not less than 50 ppm, the sulfate content was not less than 0.05%, the sulfite content was not less than 0.01%, and the iron ion content was not less than 6 ppm.

[0108] Combined with Example 5 and Comparative Example 12: Desulfurization by ozone (S 2- :O3=1:1.45) effectively oxidizes residual sulfides (such as S 2- 、S2O3 2- ), converting it into soluble SO4 2- The sulfide, sulfate and sulfite content in the final product are significantly reduced. 3+ It has better chelating ability, but if the raw material contains Fe 2 + Not completely oxidized to Fe 3+ Or if it is wrapped by sulfide to form FeS colloid, then disodium EDTA may not be able to completely remove it, but the strong oxidizing property of ozone in step S3 can synergistically remove Fe 2+ , which is converted into Fe 3+ , and forms colloidal precipitation under weak alkaline conditions of pH 6.5~8.5, which is further separated and removed in the subsequent washing process, reducing the residual iron ions to 2ppm. In addition, ozone desulfurization oxidizes sulfide into sulfate with higher water solubility, reducing the sulfide's effect on chloride ions (Cl - ) adsorption and encapsulation, making it easier to remove Cl by subsequent water washing - , ultimately achieving an increase in the purity of barium carbonate.

[0109] In summary, the method for preparing industrial barium carbonate of the present invention uses low-impurity and high-purity barium sulfide as raw material, thereby ensuring the high quality and high purity of the final barium carbonate product.

[0110] 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 producing industrial-grade barium carbonate, characterized in that: The following steps are involved: S1. After pre-treating the crude barium sulfide, the crude barium sulfide is filtered hot under an inert gas atmosphere, and then concentrated under reduced pressure and cooled to obtain a barium sulfide concentrate; S2, adjusting the barium sulfide concentrated solution of step S1 to alkaline, adding an antioxidant and a hydrolysis inhibitor thereto under stirring, and filtering through a PVDF membrane to obtain a barium sulfide solution; S3. Under the protection of inert gas, carbon dioxide is introduced into the barium sulfide solution of step S2, followed by desulfurization and washing, vacuum filtration, drying and crushing to obtain barium carbonate; The antioxidant is selected from ascorbic acid and / or disodium EDTA, and the hydrolysis inhibitor is selected from thiourea and / or sodium citrate; The mass ratio of the barium sulfide concentrate, the antioxidant and the hydrolysis inhibitor is 1000: (0.5-1.0): (0.6-1.2).

2. The method for producing industrial-grade barium carbonate according to claim 1, wherein In step S1, the temperature of the hot filtration is 60-70° C. and the pressure is 0.05-1 MPa.

3. The production method of industrial grade barium carbonate as claimed in claim 2, wherein In step S1, the pressure of the reduced pressure concentration is -0.08 to -0.1 MPa, and the concentration of the barium sulfide concentrate is 20 to 22%.

4. The method for producing industrial-grade barium carbonate according to claim 1, wherein In step S2, the pH value of the barium sulfide concentrated solution in step S1 is adjusted to 9.5-10.

5. The method for producing industrial-grade barium carbonate according to claim 4, wherein: In step S2, the pore size of the PVDF membrane is 0.22-0.26 μm.

6. The method for producing industrial-grade barium carbonate according to claim 1, wherein: In step S3, the carbon dioxide is introduced at a rate of 0.3-0.5 L / min until the pH value of the mixed solution is 8-8.5; and then at a rate of 1.5-1.8 L / min until the pH value of the mixed solution is 6.5-7.

7. The method for producing industrial-grade barium carbonate according to claim 1, wherein: In step S3, the desulfurizing agent is ozone with a volume fraction of 8 to 12%; the ozone and S 2- The molar ratio is 1.2~1.5:1.

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