Electronic grade barium carbonate and preparation method thereof

Abstract

The invention discloses an electronic-grade barium carbonate and a preparation method thereof. The preparation method is as follows: dissolving barium chloride in double distilled water to prepare a barium chloride solution; dissolving sodium carbonate in double distilled water to prepare a sodium carbonate solution; adding a surfactant to the sodium carbonate solution, stirring at a constant temperature to obtain a mixed solution; adding a crystal form control agent to the barium chloride solution, then dropwise adding the mixture into the mixed solution, stirring for reaction, centrifuging and washing the product to obtain a crude barium carbonate product; roasting the crude barium carbonate product to obtain the electronic-grade barium carbonate; the purity of the prepared barium carbonate is above 99.9%, the content of impurity ions such as iron, calcium, sodium, magnesium, strontium, etc. is extremely low, and D 50 0.4μm, spherical shape, BET 10~30m 2 / g, which can fully meet the needs of producing precision high-end electronic components.

Description

Technical Field

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

[0002] BaCO3 is one of the important inorganic chemical products and one of the most important barium salts. It is widely used in industries such as picture tubes, batteries, capacitors, ceramics, enamel, optical glass, pigments, coatings, rubber, paints, ferrites, welding rods, water treatment, steel carburizing, radio components, bricks for high-rise buildings, barium salt manufacturing, and as a precursor material for the preparation of superconductors and ceramic materials.

[0003] my country is rich in barium salt resources, ranking first in the world, and is a major producer and consumer of barium carbonate. Since the 1980s, with the rapid development of the electronics and information industries, the demand for barium has been increasing. As one of the important barium salts, BaCO3 has developed very rapidly in recent years. In addition to meeting the domestic market, the product is also exported in large quantities.

[0004] In recent years, with the advancement of science and technology and the increasing application of barium carbonate, companies have higher and higher requirements for the quality of barium carbonate crystals. The preparation of barium carbonate powder with controllable morphology and size and uniform distribution has become a hot topic in current research. Therefore, it is of great significance to study a stable and feasible method for preparing barium carbonate crystals of different morphologies and sizes.

[0005] Since BaCO3 has strong X-ray shielding ability, adding BaCO3 to the glass shell of color TV or computer picture tube can effectively absorb X-rays and α rays generated by high voltage current, which has a protective effect on the human body. Nowadays, the widespread use of LCD TV, plasma TV and computers has significantly increased the consumption of barium carbonate used in the production of picture tubes. In addition, barium carbonate can also be used in the production of radiation filters to absorb high-intensity radiation, and high-purity barium carbonate can be used in the production of miniaturized, millimeter-level chip capacitors, and its purity is required to be 99.99%.

[0006] Barium carbonate has excellent magnetic properties. Adding barium carbonate to ferrite can improve its magnetic properties. For example, after adding BaCO3 to barium ferrite, it has the characteristics of high coercive field strength and excellent magnetic properties. BaCO3 used as a magnetic material requires high purity, very low strontium and sodium impurity content in the powder, and the crystal diameter must be within a certain range.

[0007] Adding BaCO3 to ceramics can effectively reduce pores and bubbles, improve the translucency of ceramics, expand the sintering range, and increase the thermal expansion coefficient. Using powdered barium carbonate in structural ceramics can improve the hardness of tiles and increase wear resistance and chemical corrosion resistance.

[0008] Chinese patent document CN202011060142.9 discloses a method for preparing anhydrous barium carbonate crystals with special morphology, comprising the following steps: respectively preparing a barium chloride solution with a concentration of 0.01 to 1 mol / L and a sodium carbonate solution with a concentration of 0.01 mol / L; adding a crystal form controller to the barium chloride solution and stirring to form a primary solution; adding a sodium carbonate solution to the primary solution, stirring and heating to 30 to 70°C for a hydrothermal reaction to obtain a reaction slurry; filtering the reaction slurry, washing the white precipitate with deionized water to remove chloride ions, and drying it with an electric blower dryer to form spherical and petal-shaped anhydrous barium carbonate crystals; however, there is room for further improvement in the purity and particle size of the barium carbonate. Summary of the invention

[0009] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide an electronic grade barium carbonate and a preparation method thereof, wherein the purity of the prepared barium carbonate is above 99.9%, the content of impurity ions such as iron, calcium, sodium, magnesium, strontium, etc. is extremely low, and D 50 0.4μm, spherical shape, BET 10~30m 2 / g, which can fully meet the needs of producing precision high-end electronic components.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] A method for preparing electronic grade barium carbonate comprises the following steps:

[0012] (1) dissolving barium chloride in double distilled water to prepare a barium chloride solution;

[0013] (2) dissolving sodium carbonate in double distilled water to prepare a sodium carbonate solution;

[0014] (3) adding a surfactant to the sodium carbonate solution and stirring at a constant temperature to obtain a mixed solution;

[0015] (4) adding a crystal form control agent to the barium chloride solution, and then dropwise adding the crystal form control agent to the mixed solution obtained in step (3), stirring for reaction, centrifuging and washing the product to obtain a crude barium carbonate product;

[0016] (5) roasting the crude barium carbonate to obtain the electronic grade barium carbonate.

[0017] Preferably, in step (1), the concentration of the barium chloride solution is 0.5 to 1 mol / L.

[0018] Preferably, in step (2), the concentration of the sodium carbonate solution is 0.5 to 1 mol / L.

[0019] Preferably, in step (3), the surfactant is one or more of sodium hexametaphosphate, stearic acid, sodium tripolyphosphate, lecithin, sorbitan fatty acid, polysorbate, and sodium pyrophosphate; and the mass ratio of the surfactant to sodium carbonate is 1:10 to 100.

[0020] Preferably, in step (3), the constant temperature stirring condition is stirring at 30 to 50° C. for 30 to 90 minutes.

[0021] Preferably, in step (4), the method for preparing the crystal form control agent comprises the following steps: dissolving hydroxypropyl methylcellulose in deionized water, adjusting the pH of the solution, then dropping phytic acid, reacting at a constant temperature, centrifuging, washing, drying and grinding the product to obtain the crystal form control agent.

[0022] Preferably, the concentration of hydroxypropyl methylcellulose is 20-40wt%, the pH value of the solution is adjusted to 7.2-7.8 with 0.1mol / L ammonia water, the constant temperature reaction condition is stirring and reacting at 40-60°C for 3-8h; the centrifuge is washed 3-5 times with double distilled water and anhydrous ethanol respectively, and vacuum dried at 30-60°C for 12-24h; the mass ratio of phytic acid to hydroxypropyl methylcellulose is 0.1-5:100.

[0023] Preferably, in step (4), the stirring reaction conditions are 40-60° C., 50-100 r / min, and 2-6 hours; the mass ratio of the crystal form control agent to barium chloride is 1-5:100.

[0024] Preferably, in step (5), the calcination is divided into two stages with gradient control, the first stage is 230-250° C., calcination for 60-90 min, and the second stage is 630-660° C., calcination for 30-60 min.

[0025] The present invention also claims protection for electronic grade barium carbonate prepared by the preparation method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The present invention provides an electronic grade barium carbonate with a purity of ≥99.9wt%, Fe≤0.003wt%, Ca≤0.005wt%, Na≤0.001wt%, Mg≤0.001wt%, Sr≤0.005wt%, Cl≤0.035wt%, D50 of 0.4μm, and BET of 10-30m 2 / g, which can fully meet the needs of producing precision high-end electronic components.

[0028] 2) The present invention provides a method for preparing electronic grade barium carbonate, which uses a crystal form control agent to control the morphology and particle size of barium carbonate. When the molar ratio of barium chloride to sodium carbonate is 1:1, there are equal amounts of barium ions and carbonate ions on the surface of barium carbonate particles, and the negatively charged phosphate groups attract the positively charged barium ions, while the positively charged barium ions attract the nearby carbonate ions, thereby causing the two ions to be adsorbed in equal proportions near the crystal form control agent and grow into barium carbonate microspheres; adding a surfactant before the reaction of barium chloride and sodium carbonate can solve the agglomeration problem of precipitation and shorten the digestion time of precipitation, thereby improving the uniformity of product particle size; the gradient control technology is used in the roasting process, which can effectively reduce the influence of roasting on the characteristics of barium carbonate powder, reduce the aggregation of powder, and ensure the uniformity of product particle size, thereby obtaining barium carbonate with good crystal form and stable quality.

[0029] 3) The present invention provides a crystal form controller, which uses phytic acid with multiple esterifiable, complexed, and chelated phosphate groups to modify hydroxypropyl methylcellulose, so that it is covalently cross-linked with the hydroxyl group in the hydroxypropyl methylcellulose, and the resulting crystal form controller can control the particle size and morphology of barium carbonate crystals; the crystal form controller can reduce the surface adsorption force of barium carbonate powder, form a double electric layer at the interface, and the particle surfaces repel each other due to the directional steric hindrance of the hydrophilic adsorption layer, resulting in the separation of powder particles, thereby promoting particle refinement and preventing the formation of impurity crystals; in addition, since the crystal form controller has a polymer chain structure, barium ions are easy to produce covalent structures with the phosphate groups on the molecular chain of the crystal form controller, so that a large number of barium ions and carbonate ions are enriched near the molecular chain, so that barium carbonate forms a large number of barium carbonate crystal nuclei in the chemical microenvironment adjacent to the macromolecular chain, and the crystal form controller with a large number of barium carbonate crystal nuclei can further adsorb to the surface of the barium carbonate particles, inhibit the tendency of the particles to further grow along a specific direction, and promote the growth of barium carbonate particles on the macromolecular chain of the crystal form controller, thereby producing a spherical morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show schematic diagrams of certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a SEM image of the electronic grade barium carbonate provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiments. Of course, the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0033] Unless otherwise specified, the chemical reagents and materials in the present invention are purchased from commercial sources or synthesized from raw materials purchased from commercial sources.

[0034] Hydroxypropyl methylcellulose was type I with a viscosity of 20,000 mPa·s and was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0035] A method for preparing electronic grade barium carbonate comprises the following steps:

[0036] (1) dissolving barium chloride in double distilled water to prepare a 0.5-1 mol / L barium chloride solution;

[0037] (2) dissolving sodium carbonate in double distilled water to prepare a 0.5-1 mol / L sodium carbonate solution;

[0038] (3) adding a surfactant to the sodium carbonate solution, stirring at 30 to 50° C. for 30 to 90 minutes to obtain a mixed solution; the surfactant is one or more of sodium hexametaphosphate, stearic acid, sodium tripolyphosphate, lecithin, fatty acid sorbitan, polysorbate, and sodium pyrophosphate; the mass ratio of the surfactant to the sodium carbonate is 1:10 to 100;

[0039] (4) dissolving hydroxypropyl methylcellulose in deionized water to obtain a 20-40 wt% hydroxypropyl methylcellulose solution, adjusting the pH of the solution to 7.2-7.8 with 0.1 mol / L ammonia water, then dropping phytic acid, stirring and reacting at 40-60° C. for 3-8 hours, centrifuging the product, washing the centrifuge with double distilled water and anhydrous ethanol for 3-5 times, respectively, drying and grinding to obtain the crystal form control agent; the mass ratio of phytic acid to hydroxypropyl methylcellulose is 0.1-5:100;

[0040] (5) adding a crystal form control agent to the barium chloride solution, and then dropwise adding the crystal form control agent to the mixed solution obtained in step (3), controlling the molar ratio of sodium carbonate to barium chloride to be 1 to 1.05:1, stirring the mixture at 40 to 60° C. and 50 to 100 r / min for 2 to 6 hours, centrifuging and washing the product to obtain a crude barium carbonate product; the mass ratio of the crystal form control agent to the barium chloride is 1 to 5:100;

[0041] (6) The crude barium carbonate is calcined in two stages, the first stage is 230-250° C., calcined for 60-90 min, and the second stage is 630-660° C., calcined for 30-60 min, to obtain the electronic grade barium carbonate.

[0042] The present invention will be further described below through specific embodiments.

[0043] Example 1

[0044] A method for preparing electronic grade barium carbonate comprises the following steps:

[0045] (1) dissolving barium chloride in double distilled water to prepare a 1 mol / L barium chloride solution;

[0046] (2) dissolving sodium carbonate in double distilled water to prepare a 1 mol / L sodium carbonate solution;

[0047] (3) adding 10 g of polysorbate surfactant to 100 g of sodium carbonate solution, stirring at 50° C. for 30 min to obtain a mixed solution;

[0048] (4) dissolving 10 g of hydroxypropyl methylcellulose in deionized water to obtain a 40 wt % hydroxypropyl methylcellulose solution, adjusting the pH of the solution to 7.6 with 0.1 mol / L ammonia water, then dropping 0.5 g of phytic acid, stirring and reacting at 60° C. for 3 h, centrifuging the product, washing the centrifuge with double distilled water and anhydrous ethanol for 5 times, respectively, drying and grinding to obtain the crystal form control agent;

[0049] (5) adding 5 g of a crystal form control agent to 100 g of a barium chloride solution, and then dropwise adding the mixture to the mixed solution obtained in step (3), controlling the molar ratio of sodium carbonate to barium chloride to be 1:1, stirring at 60° C. and 100 r / min for 2 h, centrifuging and washing the product to obtain a crude barium carbonate product;

[0050] (6) The crude barium carbonate is calcined in two stages, the first stage is 250° C. for 60 min, and the second stage is 660° C. for 30 min, to obtain the electronic grade barium carbonate.

[0051] like Figure 1 As shown, the barium carbonate prepared in this example has a uniform particle size distribution, spherical particles, and a purity of ≥99.9wt%, D 50 The surface area is 0.45 μm and the specific surface area is 22.1 m 2 / g.

[0052] Example 2

[0053] A method for preparing electronic grade barium carbonate comprises the following steps:

[0054] (1) dissolving barium chloride in double distilled water to prepare a 0.75 mol / L barium chloride solution;

[0055] (2) dissolving sodium carbonate in double distilled water to prepare a 0.75 mol / L sodium carbonate solution;

[0056] (3) adding 5 g of polysorbate surfactant to 100 g of sodium carbonate solution and stirring at 40° C. for 60 min to obtain a mixed solution;

[0057] (4) dissolving 10 g of hydroxypropyl methylcellulose in deionized water to obtain a 30 wt % hydroxypropyl methylcellulose solution, adjusting the pH of the solution to 7.6 with 0.1 mol / L ammonia water, then dropping 0.25 g of phytic acid, stirring and reacting at 50° C. for 5 h, centrifuging the product, washing the centrifuge with double distilled water and anhydrous ethanol for 4 times, respectively, drying and grinding to obtain the crystal form control agent;

[0058] (5) adding 3 g of a crystal form control agent to 100 g of a barium chloride solution, and then dropwise adding the mixture to the mixed solution obtained in step (3), controlling the molar ratio of sodium carbonate to barium chloride to be 1:1, stirring at 50° C. and 75 r / min for 4 h, centrifuging and washing the product to obtain a crude barium carbonate product;

[0059] (6) The crude barium carbonate is calcined in two stages, the first stage is 240° C. for 75 min, and the second stage is 650° C. for 45 min, to obtain the electronic grade barium carbonate.

[0060] The barium carbonate prepared in this example has a uniform particle size distribution, is spherical, and has a purity of ≥99.9wt%, D 50 The surface area is 0.39 μm and the specific surface area is 27.6 m 2 / g.

[0061] Example 3

[0062] A method for preparing electronic grade barium carbonate comprises the following steps:

[0063] (1) dissolving barium chloride in double distilled water to prepare a 0.5 mol / L barium chloride solution;

[0064] (2) dissolving sodium carbonate in double distilled water to prepare a 0.5 mol / L sodium carbonate solution;

[0065] (3) adding 1 g of polysorbate surfactant to 100 g of sodium carbonate solution, stirring at 30° C. for 90 min to obtain a mixed solution;

[0066] (4) dissolving 10 g of hydroxypropyl methylcellulose in deionized water to obtain a 20 wt % hydroxypropyl methylcellulose solution, adjusting the pH of the solution to 7.6 with 0.1 mol / L ammonia water, then dropping 0.1 g of phytic acid, stirring and reacting at 40° C. for 3 h, centrifuging the product, washing the centrifuge with double distilled water and anhydrous ethanol for 3 times, respectively, drying and grinding to obtain the crystal form control agent;

[0067] (5) adding 1 g of a crystal form control agent to 100 g of a barium chloride solution, and then dropwise adding the mixture to the mixed solution obtained in step (3), controlling the molar ratio of sodium carbonate to barium chloride to be 1:1, stirring at 40° C. and 50 r / min for 6 h, centrifuging and washing the product to obtain a crude barium carbonate product;

[0068] (6) The crude barium carbonate is calcined in two stages, the first stage is 230° C. for 90 min, and the second stage is 630° C. for 60 min, to obtain the electronic grade barium carbonate.

[0069] The barium carbonate prepared in this example has a uniform particle size distribution, is spherical, and has a purity of ≥99.9wt%, D 50 The surface area is 0.32 μm and the specific surface area is 31.7 m 2 / g.

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing electronic grade barium carbonate, characterized in that: The steps include: (1) Dissolve barium chloride in double distilled water to prepare a barium chloride solution; (2) dissolving sodium carbonate in double distilled water to prepare a sodium carbonate solution; (3) adding a surfactant to the sodium carbonate solution and stirring at a constant temperature to obtain a mixed solution; (4) adding a crystal form control agent to the barium chloride solution, and then dropwise adding the crystal form control agent to the mixed solution obtained in step (3), stirring for reaction, centrifuging and washing the product to obtain a crude barium carbonate product; (5) roasting the crude barium carbonate to obtain the electronic grade barium carbonate; In step (4), the method for preparing the crystal form control agent comprises the following steps: dissolving hydroxypropyl methylcellulose in deionized water, adjusting the pH of the solution, then dropping phytic acid, reacting at a constant temperature, centrifuging, washing, drying and grinding the product to obtain the crystal form control agent.

2. The preparation method according to claim 1, characterized in that: In step (1), the concentration of the barium chloride solution is 0.5-1 mol / L.

3. The preparation method according to claim 1, characterized in that: In step (2), the concentration of the sodium carbonate solution is 0.5-1 mol / L.

4. The preparation method according to claim 1, characterized in that: In step (3), the surfactant is one or more of sodium hexametaphosphate, stearic acid, sodium tripolyphosphate, lecithin, sorbitan fatty acid, polysorbate, and sodium pyrophosphate; and the mass ratio of the surfactant to sodium carbonate is 1:10-100.

5. The preparation method according to claim 1, characterized in that: In step (3), the constant temperature stirring condition is stirring at 30-50° C. for 30-90 min.

6. The preparation method according to claim 1, characterized in that: The concentration of hydroxypropyl methylcellulose is 20-40wt%, the pH value of the solution is adjusted to 7.2-7.8 with 0.1 mol / L ammonia water, the constant temperature reaction condition is stirring reaction at 40-60℃ for 3-8h; the centrifuge is washed 3-5 times with double distilled water and anhydrous ethanol respectively, and vacuum dried at 30-60℃ for 12-24h; the mass ratio of phytic acid to hydroxypropyl methylcellulose is 0.1-5:

100.

7. The preparation method according to claim 1, characterized in that: In step (4), the stirring reaction conditions are 40-60° C., 50-100 r / min, and 2-6 hours; the mass ratio of the crystal form control agent to barium chloride is 1-5:

100.

8. The preparation method according to claim 1, characterized in that: In step (5), the calcination is divided into two stages with gradient control, the first stage is 230-250°C, calcination is 60-90 min, and the second stage is 630-660°C, calcination is 30-60 min.

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