Preparation method of nanoscale barium carbonate

Abstract

The invention relates to the technical field of preparation of barium carbonate, and discloses a preparation method of nanoscale barium carbonate, which comprises the following steps: (1) weighing sodium carbonate and adding into deionized water to obtain a sodium carbonate solution, (2) adding barite powder into the sodium carbonate solution, heating to a boiling state, reacting, and filtering to obtain filter residues, (3) adding an ammonium chloride solution into the filter residues, and filtering to obtain the nanoscale barium carbonate. (4) adding a first conditioning agent into the first reaction solution, and then introducing air through a membrane dispersion method to obtain a nano-bubble reaction solution, and (5) adding a second conditioning agent into the second reaction solution to obtain a third reaction solution, and carrying out vacuum filtration to obtain a finished product. (6) slowly dropwise adding the third reaction solution into the nano-bubble reaction solution, stirring at normal temperature, filtering, washing and drying to obtain nano-scale barium carbonate; the method has the effects of no tail gas emission, high purity and reduced production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of barium carbonate preparation, and particularly relates to a method for preparing nanoscale barium carbonate. Background Art

[0002] Barium carbonate is an important inorganic salt product and has wide application value in industrial fields such as ceramics and electronics. Different industrial fields have different requirements for the morphology of barium carbonate particles, and the quality requirements for barium carbonate are also getting higher and higher.

[0003] In industry, barium carbonate is usually prepared by the carbonization method, that is, using barite (BaSO4) as the raw material, generating barium sulfide through high-temperature reduction, and then reacting with carbon dioxide to generate barium carbonate; however, the H2S gas generated by the carbonization method is toxic and needs to be properly treated subsequently. At the same time, there are more impurities in the barium carbonate prepared by the carbonization method. When used for the production of electronic devices, further impurity removal is required through ion exchange or membrane separation, resulting in an increase in production costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing nanoscale barium carbonate, which has the effects of no tail gas emission, high purity, and reduced production cost.

[0005] The above technical purpose of the present invention is achieved through the following technical solutions. A method for preparing nanoscale barium carbonate includes the following steps:

[0006] (1) Weigh sodium carbonate and add it to deionized water, heat to 30 °C and stir to dissolve to obtain a sodium carbonate solution;

[0007] (2) Add barite powder to the sodium carbonate aqueous solution obtained in step (1). The weight ratio of the barite powder to the sodium carbonate is 2:1. Heat to the boiling state and stir for reaction for 70 min, and then filter to obtain a filter residue;

[0008] (3) Add a 25% ammonium chloride solution to the filter residue obtained in step (2). The volume ratio of the ammonium chloride solution to the sodium carbonate solution is 3:2. Heat to the boiling state and stir for reaction for 4 h, and then filter to obtain a first reaction solution. At the same time, recover the distillate during the reaction to obtain a second reaction solution;

[0009] (4) Add a first regulator to the first reaction solution obtained in step (3), stir evenly, and then pass air through the membrane dispersion method to obtain a nano-bubble reaction solution;

[0010] (5) Add a second regulator to the second reaction solution obtained in step (3), stir evenly to obtain a third reaction solution;

[0011] (6) Slowly add the third reaction solution obtained in step (5) to the nano-bubble reaction solution obtained in step (4), stir at room temperature for 1.5 - 2 h, then filter, wash with deionized water 2 - 3 times, and dry to obtain nano-sized barium carbonate.

[0012] The further setting of the present invention is that the concentration of nano-bubbles in the nano-bubble reaction solution is 2.8 - 3.0×10 8 per mL.

[0013] The further setting of the present invention is that the first regulator is a 50% ethanol solution, and the volume ratio of the ethanol solution to the first reaction solution is 1:1.

[0014] The further setting of the present invention is that the second regulator is sodium alginate, and the weight ratio of the sodium alginate to the sodium carbonate is 1:40.

[0015] The further setting of the present invention is that the mass fraction of the sodium carbonate solution is 28.4%.

[0016] The beneficial effects of the present invention are:

[0017] 1. The present invention uses barite and sodium carbonate as raw materials. First, barite powder and saturated sodium carbonate (the saturated concentration of sodium carbonate at 30 °C is 28.4%) are subjected to the first conversion under long-term boiling conditions to convert barium sulfate precipitation into barium carbonate precipitation. Then, ammonium chloride is added to the filter residue obtained by filtration for ammonolysis reaction. The first reaction solution obtained by filtration is barium chloride solution, and the second reaction solution collected is ammonium carbonate solution. Then, the recycled fraction of ammonium carbonate solution is added to the barium chloride solution for the second conversion to convert barium ions in the solution into barium carbonate precipitation; in this process, impurities (such as silicon dioxide) in the barite powder can be removed by dissolving and filtering with ammonium chloride solution after the first conversion, greatly improving the purity of the product sodium carbonate. At the same time, during the whole reaction process, the reaction conditions are mild, the conversion is in the whole solution state, there is no high-temperature calcination and no tail gas emission, and high-purity barium carbonate is obtained. Using barite and sodium carbonate as raw materials can also greatly reduce the production cost.

[0018] 2. After the first reaction solution is prepared in the present invention, an appropriate amount of ethanol solution is added, and then nano-bubble reaction solution is prepared by introducing air using the membrane dispersion method. Since the first reaction solution is barium chloride solution, when an ethanol solution is added and then nano-bubble reaction solution is prepared by introducing air using the membrane dispersion method, on the one hand, barium chloride molecules are dispersed in the ethanol solution, and the ethoxy group has an electrostatic interaction with Ba 2+ to increase the reaction rate and generate barium ethoxide [Ba(OC2H5)2] with high activity, avoiding the adsorption of barium ions on the surface of nano-bubbles and destroying the original double-layer structure of nano-bubbles. On the other hand, through the OH in a large number of ethanol molecules- Adsorbed on the surface of the bubbles, it increases the thickness of the double electric layer and further enhances the stability of the nano-bubble reaction solution. After dropping the third reaction solution, ammonium carbonate generates CO3 - under the action of OH 2- and hydrated ammonia. At the same time, CO3 2- reacts with barium ethoxide to obtain amorphous barium carbonate. However, due to its loose internal structure, it will quickly transform into vaterite type. During this process, the charged nano-bubbles on the surface can adhere to the surface of barium carbonate. By changing the solid-liquid interfacial tension on the surface, it helps to reduce the subsequent crystal nucleation rate of barium carbonate; the surface nano-bubbles also act as a dispersant to prevent the heterogeneous nucleation of barium carbonate crystals and avoid the lateral growth on the surface of barium carbonate; at the same time, nano-bubbles can also physically adsorb Ba 2+ on the nano-bubble interface, reducing the chance of Ba 2+ combining with CO3 2- ions, thereby reducing the nucleation rate and crystal growth rate of barium carbonate, and thus realizing the grain refinement of barium carbonate. Since the growth rate of barium carbonate crystal nuclei is slow, the grains do not grow. Affected by the strong electric field of -OH in the solvent ethanol, the particles do not grow, resulting in a decrease in the surface energy of the particles, and fine and uniform vaterite barium carbonate dissolves out; the -COO- groups in sodium alginate will also adsorb on specific crystal planes of barium carbonate, inhibiting the growth of crystal planes. At the same time, alginate and ethoxide are impurities to each other, and can also interfere with the nucleation of some barium carbonate to form amorphous barium carbonate, which is then transformed into vaterite-shaped barium carbonate; at the same time, aragonite barium carbonate grows in a splitting manner, and alginate can be adsorbed on the specific surface of aragonite grains through -COO-, inhibiting the growth of the split needles, and can also control the particle size of barium carbonate to be smaller, forming a spherical morphology; in summary, by adding an ethanol solution to prepare a stable nano-bubble reaction solution, and then regulating the crystal form of barium carbonate through nano-bubbles, ethanol and sodium alginate, nano-scale high-purity vaterite barium carbonate is induced to generate.

[0019] 3. The vaterite nano-barium carbonate prepared by the present invention has low production cost, concentrated particle size distribution, the morphology of nano-barium carbonate is vaterite-shaped, and has good application prospects. Description of the Drawings

[0020] Figure 1 is the SEM image of the nano-barium carbonate prepared in Example 1 of the present invention. Detailed Embodiments

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0022] Example 1

[0023] (1) Weigh sodium carbonate and add it to deionized water. Heat it to 30 °C and stir to dissolve, obtaining a sodium carbonate solution with a mass fraction of 28.4%;

[0024] (2) Add barite powder with a particle size of 80 mm - 100 mm to the obtained aqueous sodium carbonate solution. The weight ratio of the barite powder to the sodium carbonate is 2:1. Heat it to the boiling state and stir for 70 min, then filter to obtain a filter residue;

[0025] (3) Add a 25% ammonium chloride solution to the obtained filter residue. The volume ratio of the ammonium chloride solution to the sodium carbonate solution is 3:2. Heat it to the boiling state and stir for 4 h, then filter to obtain a first reaction solution (i.e., barium chloride solution), and at the same time recover the distillate during the reaction to obtain a second reaction solution (i.e., ammonium carbonate solution);

[0026] (4) Add an equal volume of 50% ethanol solution to the obtained first reaction solution, stir evenly, and then pass air through it by the membrane dispersion method to obtain a nano-bubble reaction solution. The concentration of nano-bubbles in the nano-bubble reaction solution is 2.8×10 8 per mL;

[0027] (5) Add sodium alginate to the obtained second reaction solution. The addition amount of sodium alginate is 2.5% of the weight of sodium carbonate, stir evenly to obtain a third reaction solution;

[0028] (6) Slowly drop the third reaction solution into the obtained nano-bubble reaction solution, stir at room temperature for 1.5 h, then filter, wash with deionized water twice, and dry at a temperature of 105 - 110 °C to obtain nano-scale barium carbonate.

[0029] As Figure 1 shown, the nano-barium carbonate particles prepared in this example are spherical, with a purity of 99.8% and an average particle size of 186 nm.

[0030] Example 2

[0031] (1) Weigh sodium carbonate and add it to deionized water. Heat it to 30 °C and stir to dissolve, obtaining a sodium carbonate solution with a mass fraction of 28.4%;

[0032] (2) Add barite powder with a particle size of 80 mm - 100 mm to the aqueous sodium carbonate solution obtained in step (1). The weight ratio of the barite powder to the sodium carbonate is 2:1. Heat to the boiling state and stir for reaction for 70 min, and then filter to obtain a filter residue.

[0033] (3) Add a 25% ammonium chloride solution to the filter residue obtained in step (2). The volume ratio of the ammonium chloride solution to the sodium carbonate solution is 3:2. Heat to the boiling state and stir for reaction for 4 h, and then filter to obtain a first reaction solution. At the same time, recover the distillate during the reaction to obtain a second reaction solution.

[0034] (4) Add an ethanol solution with the same volume of 50% to the first reaction solution obtained in step (3), stir evenly, and then introduce air through the membrane dispersion method to obtain a nano-bubble reaction solution. The concentration of nano-bubbles in the nano-bubble reaction solution is 2.9×10 8 per mL;

[0035] (5) Add sodium alginate to the second reaction solution obtained in step (3). The addition amount of sodium alginate is 2.5% of the weight of sodium carbonate, and stir evenly to obtain a third reaction solution.

[0036] (6) Slowly drop the third reaction solution obtained in step (5) into the nano-bubble reaction solution obtained in step (4), stir at room temperature for 2 h, then filter, wash with deionized water 3 times, and dry at a temperature of 105 - 110 °C to obtain nano-sized barium carbonate.

[0037] The nano-sized barium carbonate particles prepared in this example are spherical, with a purity of 99.8% and an average particle size of 193 nm.

[0038] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0039] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A preparation method of nanoscale barium carbonate, characterized in that, It includes the following steps: (1) Weigh sodium carbonate and add it to deionized water. Heat it to 30 °C and stir to dissolve, obtaining a sodium carbonate solution; (2) Add barite powder to the aqueous sodium carbonate solution obtained in step (1). The weight ratio of the barite powder to the sodium carbonate is 2:

1. Heat it to the boiling state and stir for reaction for 70 min, then filter to obtain filter residue; (3) Add a 25% ammonium chloride solution to the filter residue obtained in step (2). The volume ratio of the ammonium chloride solution to the sodium carbonate solution is 3:

2. Heat it to the boiling state and stir for reaction for 4 h, then filter to obtain a first reaction solution. At the same time, recover the distillate during the reaction to obtain a second reaction solution; (4) Add a first regulator to the first reaction solution obtained in step (3), stir evenly, and then introduce air through the membrane dispersion method to obtain a nano-bubble reaction solution; (5) Add a second regulator to the second reaction solution obtained in step (3), stir evenly to obtain a third reaction solution; (6) Slowly dropwise add the third reaction solution obtained in step (5) to the nano-bubble reaction solution obtained in step (4), stir at room temperature for 1.5 - 2 h, then filter, wash with deionized water 2 - 3 times, and dry to obtain nano-sized barium carbonate.

2. The preparation method of a nanoscale barium carbonate according to claim 1, wherein: The concentration of nanobubbles in the nanobubble reaction solution is 2.8 to 3.0×10 8 per mL.

3. The preparation method of a nanoscale barium carbonate according to claim 1, characterized in that: The first regulator is a 50% ethanol solution, and the volume ratio of the ethanol solution to the first reaction solution is 1:

1.

4. The preparation method of a nanoscale barium carbonate according to claim 1, characterized in that: The second regulator is sodium alginate, and the weight ratio of the sodium alginate to the sodium carbonate is 1:

40.

5. The preparation method of nanoscale barium carbonate according to claim 1, characterized in that: The mass fraction of the sodium carbonate solution is 28.4%.

Images