Industrial preparation method of nano yttrium oxide for electronic ceramics

Abstract

The invention discloses an industrial preparation method of nano yttrium oxide for electronic ceramics, belonging to the field of rare earth hydrometallurgy technology. The invention first dissolves yttrium oxide in nitric acid to remove anionic impurities in yttrium oxide, then removes impurities through (NH4)2S solution to obtain a high-purity yttrium nitrate solution, then precipitates yttrium carbonate crystals through ammonia water and ammonium bicarbonate solution, and finally calcines and decomposes to obtain nano yttrium oxide for electronic ceramics. The yttrium oxide obtained by the invention is nano-sized, has a high specific surface area, and is easy to disperse. It is suitable for the electronic ceramic industry, especially for industrial production, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth hydrometallurgy, and in particular relates to an industrial preparation method of nano yttrium oxide for electronic ceramics. Background Art

[0002] Nano yttrium oxide powder is an important electronic ceramic raw material. It belongs to the cubic system and has high temperature stability, excellent heat and corrosion resistance, a melting point greater than 2400℃, and a dielectric constant of 12-20. It is a new type of high-function fine inorganic electronic material and has been widely used in the fields of aviation, aerospace, atomic energy and high-tech ceramics. These fields require that the yttrium oxide raw material should not only have a finer particle size and a more uniform distribution, but also have good dispersibility and sintering activity. Although the industry currently uses ion exchange or solvent extraction to produce Y with a purity of up to 99.99% or 99.999%, 2 O 3 However, the sintering activity of industrial powder cannot meet the use requirements of yttrium oxide powder in the above fields. Therefore, it is of great significance to study the preparation method of ultrafine yttrium oxide powder with simple production process, low production cost, controllable particle size and high activity.

[0003] The existing methods for preparing fine-grained yttrium oxide powder include precipitation method, sol-gel method, vapor deposition method, microemulsion method and hydrothermal method. The precipitation method includes oxalic acid precipitation method, carbonate precipitation method, hydroxide precipitation method, homogeneous precipitation method, complex precipitation method and the like. The biggest feature of this method is that the solution nucleates quickly, is easy to control, has simple equipment, and can produce high-purity products, but is difficult to filter and easy to agglomerate. The hydrothermal method is to accelerate and strengthen the hydrolysis reaction of ions under high temperature and high pressure conditions, and form dispersed nanocrystalline nuclei. This method can obtain nanopowders with uniform dispersion and narrow particle size distribution, but requires high temperature and high pressure equipment, which is expensive, inefficient and unsafe to operate. The gel method is to form a sol by polymerization or hydrolysis of organic metal compounds or organic complexes at low temperature, and then form a gel under certain conditions. Further heat treatment can obtain ultrafine nanopowders with large specific surface area and good dispersion. This method can be carried out under mild conditions, and the obtained powder has a large specific surface area and good dispersibility, but the reaction time is long and it takes several days to complete, which is difficult to meet the requirements of large-scale industrialization. The solid phase method is to perform high temperature decomposition through solid compound or intermediate solid phase reaction, such as mixing rare earth salt with oxalic acid or ammonium carbonate solid phase to form rare earth salt intermediate, and then high temperature decomposition to obtain ultrafine powder. This method has high reaction efficiency, simple equipment and easy operation, but the obtained powder has irregular shape and poor uniformity.

[0004] Therefore, how to provide an industrial preparation method for fine-grained, high-purity, and high-specific surface area nano-yttrium oxide for electronic ceramics has become a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an industrial preparation method of nano yttrium oxide for electronic ceramics.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides an industrial preparation method of nano yttrium oxide for electronic ceramics, comprising the following steps:

[0008] (1) dissolving yttrium oxide in a nitric acid solution to obtain an yttrium nitrate solution;

[0009] (2) the yttrium nitrate solution obtained in step (1) and (NH 4 ) 2 The S solutions are mixed and heated and stirred to obtain a high-purity yttrium nitrate solution;

[0010] (3) adding a nonionic surfactant solution to the high-purity yttrium nitrate solution obtained in step (2), and then adding aqueous ammonia to obtain a suspension;

[0011] (4) adding an ammonium bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, and then aging, filtering, washing, drying and calcining to obtain the nano yttrium oxide for electronic ceramics.

[0012] Preferably, in step (1), the concentration of the yttrium nitrate solution is 50-200 g / L.

[0013] Preferably, in step (2), the (NH 4 ) 2 The concentration of S solution is 10-200g / L; the (NH 4 ) 2 In S solution (NH 4 ) 2 The mass of S is 0.1-1% of the mass of yttrium oxide in step (1).

[0014] Preferably, in step (3), the nonionic surfactant in the nonionic surfactant solution includes one or more of PEG1000, PEG2000, PEG4000 and PEG6000; the mass of the nonionic surfactant in the nonionic surfactant solution is 1-10% of the mass of yttrium oxide in step (1).

[0015] Preferably, in step (3), the concentration of the aqueous ammonia is 10-25%, and the amount of aqueous ammonia is used to adjust the pH of the solution to 5-6.

[0016] Preferably, in step (4), the concentration of the ammonium bicarbonate solution is 50-300 g / L, the titration rate of the ammonium bicarbonate solution is 0.01-10 L / h, and the amount of the ammonium bicarbonate solution is used to adjust the pH of the solution to 7.8.

[0017] Preferably, in step (4), the temperature of the heating and stirring is 20-80° C., and the stirring speed of the heating and stirring is 100-500 rap / min.

[0018] Preferably, in step (4), the aging time is 0.5-3 h; the drying temperature is 40-150° C., and the drying time is 5-120 min.

[0019] Preferably, in step (4), the calcination temperature is 600-900° C. and the calcination time is 0.5-5 h.

[0020] The present invention also provides nano yttrium oxide for electronic ceramics prepared by the preparation method described in the above technical solution.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects:

[0022] The present invention first dissolves yttrium oxide in nitric acid to remove anionic impurities in yttrium oxide, and then (NH 4 ) 2 The yttrium oxide obtained by the present invention is nanometer-sized, has a high specific surface area, is easy to disperse, is suitable for the electronic ceramic industry, and is particularly suitable for industrial production, and has broad application prospects.

[0023] The invention adopts an ammonia water-ammonium bicarbonate two-step precipitation method to synthesize yttrium carbonate crystals, which has the characteristics of easy filtration and easy washing of impurities. The yttrium oxide particles obtained after calcination have small particle size, uniform size distribution, no hard agglomeration, looseness, good dispersibility, low cost and easy industrialization. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.

[0026] The embodiment of the present invention provides an industrial preparation method of nano yttrium oxide for electronic ceramics, comprising the following steps:

[0027] (1) dissolving yttrium oxide in a nitric acid solution to obtain an yttrium nitrate solution;

[0028] (2) the yttrium nitrate solution obtained in step (1) and (NH 4 ) 2 The S solutions are mixed and heated and stirred to obtain a high-purity yttrium nitrate solution;

[0029] (3) adding a nonionic surfactant solution to the high-purity yttrium nitrate solution obtained in step (2), and then adding aqueous ammonia to obtain a suspension;

[0030] (4) adding an ammonium bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, and then aging, filtering, washing, drying and calcining to obtain the nano yttrium oxide for electronic ceramics.

[0031] In a preferred embodiment, in step (1), the concentration of the yttrium nitrate solution is 50-200 g / L, more preferably 80-150 g / L. The cations such as iron, calcium, zinc, lead and Cl in the existing yttrium oxide with a purity of 99.9% - 、F - 、SO 4 2- The content of anionic impurities such as Cl-, F-, SO- and NH-2- are exceeded and do not meet the standards for electronic ceramics. The present invention first dissolves yttrium oxide in a nitric acid solution to prepare an yttrium nitrate solution to remove Cl-, F-, SO- and NH-2- 4 2- Such anionic impurities make the Cl in the final nano yttrium oxide for electronic ceramics - 、F - 、SO 4 2- The anionic impurities meet the standards.

[0032] In a preferred embodiment, in step (1), the purity of the yttrium oxide is 99.9%.

[0033] In a preferred embodiment, in step (2), the (NH 4 ) 2 The concentration of the S solution is 10-200 g / L, more preferably 20-100 g / L; the (NH 4 ) 2 In S solution (NH 4 ) 2 The mass of S is 0.1-1% of the mass of yttrium oxide in step (1), and more preferably 0.1-0.5%. 4 ) 2The S solution is further impurized to obtain a high-purity yttrium nitrate solution with CaO < 10 ppm and Fe 2 O 3 <10ppm, ZnO<10ppm, PbO<10ppm, Cl - 、F - 、SO 4 2- <20ppm, which is conducive to obtaining nano yttrium oxide with a purity greater than 99.99% and meeting the yttrium oxide standard for electronic ceramics.

[0034] In a preferred embodiment, in step (2), the yttrium nitrate solution and (NH 4 ) 2 After the S solution is mixed, nitric acid or yttrium oxide is added to adjust the pH of the solution to 2-3. The nitric acid in the present invention can provide H + Yttrium oxide can neutralize H when the pH of the solution is too low. + , thereby achieving the purpose of adjusting the pH value of the solution.

[0035] In a preferred embodiment, in step (2), the temperature of the heating and stirring is 20-70°C, more preferably 20-50°C; and the time of the heating and stirring is 30 minutes.

[0036] In a preferred embodiment, in step (3), the nonionic surfactant in the nonionic surfactant solution includes one or more of PEG1000, PEG2000, PEG4000 and PEG6000, more preferably one or more of PEG2000, PEG4000 and PEG6000; the mass of the nonionic surfactant in the nonionic surfactant solution is 1-10% of the mass of yttrium oxide in step (1), more preferably 1-5%. The nonionic surfactant in the present invention can wrap the yttrium carbonate crystals generated subsequently to prevent the grains from growing, and a large amount of gas is formed during the calcination of the yttrium carbonate crystals, which has a separation effect, prevents the agglomeration of yttrium oxide, and is conducive to obtaining yttrium oxide powder with good dispersibility and high specific surface area.

[0037] In a preferred embodiment, in step (3), the concentration of the aqueous ammonia is 10-25%, more preferably 15-20%; the amount of the aqueous ammonia is used to adjust the pH of the solution to 5-6. The present invention controls the concentration and amount of aqueous ammonia within the above range, which is beneficial to Y 2 (OH) 5 (NO 3 )·nH 2 O The formation of amorphous precipitate, changing the concentration of ammonia or changing the amount of ammonia will generate hexagonal phase Y(OH) 3 Crystal, unable to Y 2(CO 3 ) 3 Crystal transformation.

[0038] In a preferred embodiment, in step (4), the concentration of the ammonium bicarbonate solution is 50-300 g / L, more preferably 100-200 g / L; the titration rate of the ammonium bicarbonate solution is 0.01-10 L / h, more preferably 0.01-1 L / h; the amount of the ammonium bicarbonate solution is used to adjust the solution pH to 7.8. The present invention controls the concentration, titration rate and amount of the ammonium bicarbonate solution within the above ranges, which is beneficial to Y 2 (OH) 5 (NO 3 )·nH 2 O amorphous precipitate gradually moves to Y 2 (CO 3 ) 3 Crystal transformation, changing the concentration of ammonium bicarbonate solution will make the crystals larger or agglomerate, changing the titration rate of the ammonium bicarbonate solution will change the nucleation rate and growth rate of the crystals, changing the dosage of the ammonium bicarbonate solution will increase the loss of rare earth or increase the impurity content, making it difficult to wash and filter.

[0039] The invention adopts an ammonia water-ammonium bicarbonate two-step precipitation method to synthesize yttrium carbonate crystals, which has the characteristics of easy filtration and easy washing of impurities. The yttrium oxide particles obtained after calcination have small particle size, uniform size distribution, no hard agglomeration, looseness, good dispersibility, low cost and easy industrialization.

[0040] In a preferred embodiment, in step (4), the temperature of the heating and stirring is 20-80°C, more preferably 20-60°C; the stirring speed of the heating and stirring is 100-500 rap / min, more preferably 100-350 rap / min.

[0041] In a preferred embodiment, in step (4), the aging time is 0.5-3 hours, more preferably 0.5-2 hours; and the aging method is stirring aging. The stirring aging in the present invention helps the transformation of amorphous to crystalline, and prevents the further growth of yttrium carbonate crystals.

[0042] In a preferred embodiment, in step (4), the washing reagents are deionized water and ethanol.

[0043] In a preferred embodiment, in step (4), the drying temperature is 40-150°C, more preferably 60-90°C; the drying time is 5-120 min, more preferably 10-60 min. The present invention controls the drying temperature and time within the above ranges, which is conducive to forming a small-particle, non-agglomerated yttrium oxide precursor. Changing the drying temperature will cause hard agglomeration between particles and reduce the specific surface area. Changing the drying time will increase the agglomeration of grains and reduce the specific surface area.

[0044] In a preferred embodiment, in step (4), the drying method is microwave drying. The present invention can heat the inside and outside of the material simultaneously through microwave drying, and the surface moisture is preferentially vaporized, forming an internal pressure gradient, and the internal moisture evaporates rapidly, and the drying time is greatly shortened; the internal water molecules are vaporized to generate water vapor, which expands when heated, and the powder is split into small fragments, the specific surface area is increased and does not agglomerate, which is conducive to obtaining nano yttrium oxide with small particle size and high specific surface area.

[0045] In a preferred embodiment, in step (4), the calcination temperature is 600-900°C, more preferably 650-850°C; the calcination time is 0.5-5h, more preferably 1-3h. 2 O 3 The present invention controls the calcination temperature and time within the above range, which is conducive to the formation of cubic yttrium oxide with stable structure and complete crystal form. Changing the calcination temperature will increase the particle diffusion exponentially and the grains will grow. Changing the calcination time will cause small grains to diffuse across the grain boundaries to large grains, the grain boundaries will move, the large grains will grow further, and the small grains will be merged and disappear.

[0046] The present invention also provides nano yttrium oxide for electronic ceramics prepared by the preparation method described in the above technical solution.

[0047] The nano yttrium oxide for electronic ceramics provided by the present invention has small particle size, uniform size distribution, good dispersibility, few impurities and high specific surface area.

[0048] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0049] The room temperature in the embodiments of the present invention refers to 25±3°C.

[0050] Examples 1-5

[0051] An industrial preparation method of nano yttrium oxide for electronic ceramics:

[0052] (1) Yttrium oxide powder with a purity of 99.9% is dissolved in nitric acid to obtain yttrium nitrate solution.

[0053] (2) Add (NH4 ) 2 S solution, then add nitric acid or yttrium oxide powder to adjust the solution pH to 2-3, heat and stir for 30 minutes, filter, and obtain a high-purity yttrium nitrate solution.

[0054] (3) dissolving a nonionic surfactant in deionized water to obtain a nonionic surfactant solution, then adding the high-purity yttrium nitrate solution obtained in step (2), and then titrating with ammonia water until the solution pH = 5-6 to obtain a suspension.

[0055] (4) adding ammonium bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions until the pH value of the solution is 7.8, stirring, aging and filtering to obtain yttrium carbonate crystals.

[0056] (5) The yttrium carbonate crystals obtained in step (4) are washed alternately with deionized water and ethanol, then microwave-dried in a microwave field, and then placed in a muffle furnace for calcination to obtain nano yttrium oxide for electronic ceramics.

[0057] The process parameters of Examples 1-5 are shown in Table 1.

[0058] Table 1 Process parameters of Examples 1-5

[0059]

[0060]

[0061] Example 6

[0062] The difference from Example 1 is that the nonionic surfactant PEG4000 in step (3) is replaced by PEG1000, and the rest is the same as Example 1.

[0063] Comparative Example 1

[0064] (3) adding a nonionic surfactant to the high-purity yttrium nitrate solution obtained in step (2), and then titrating with aqueous ammonia until the pH value of the solution is 5-6 to obtain a suspension;

[0065] Steps (1)-(2) and steps (4)-(5) are the same as those in Example 1.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that the stirring aging in step (4) is replaced by static aging, and the rest is the same as Example 1.

[0068] Comparative Example 3

[0069] The difference from Example 1 is that the alternating washing with deionized water and ethanol in step (5) is replaced by washing with deionized water, and the rest is the same as Example 1.

[0070] Comparative Example 4

[0071] The difference from Example 1 is that the microwave drying in a microwave field in step (5) is replaced by drying in a drying oven, and the rest is the same as Example 1.

[0072] Table 2 Y prepared in Example 6 and Comparative Examples 1-4 2 O 3 Powder properties

[0073] Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 <![CDATA[Y 2 O 3 Yield (%)]]> 99.3 99.1 98.5 99.5 98.2 <![CDATA[Y 2 O 3 Powder particle size (D50, μm)]]> 0.83 6.16 3.65 10.78 12.07 <![CDATA[Y 2 O 3 Powder specific surface area (m 2 / g)]]> 35.26 19.10 22.92 20.26 10.96 <![CDATA[Y 2 O 3 Powder purity (%)]]> 99.99 99.90 99.35 99.43 99.98

[0074] As can be seen from Table 2, changing the addition method of nonionic surfactant, aging method, washing reagent and drying method will affect Y 2 O 3 Yield, particle size and specific surface area of ​​powder.

[0075] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An industrial preparation method of nano yttrium oxide for electronic ceramics, characterized in that: The following steps are involved: (1) dissolving yttrium oxide in a nitric acid solution to obtain an yttrium nitrate solution; the concentration of the yttrium nitrate solution is 100-200 g / L; (2) mixing the yttrium nitrate solution obtained in step (1) and the (NH4)2S solution, heating and stirring, to obtain a high-purity yttrium nitrate solution; (3) adding a nonionic surfactant solution to the high-purity yttrium nitrate solution obtained in step (2), and then adding ammonia water to obtain a suspension; the concentration of the ammonia water is 10-25%, and the amount of ammonia water is used to adjust the pH of the solution to 5-6; (4) adding an ammonium bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, and then aging, filtering, washing, drying and calcining to obtain the nano yttrium oxide for electronic ceramics; the concentration of the ammonium bicarbonate solution is 50-300 g / L, the titration rate of the ammonium bicarbonate solution is 0.01-10 L / h, and the amount of the ammonium bicarbonate solution is used to adjust the pH of the solution to 7.

8.

2. The industrial preparation method of nano yttrium oxide for electronic ceramics according to claim 1, characterized in that: In step (2), the concentration of the (NH4)2S solution is 10-200 g / L; the mass of (NH4)2S in the (NH4)2S solution is 0.1-1% of the mass of yttrium oxide in step (1).

3. The industrial preparation method of nano yttrium oxide for electronic ceramics according to claim 1, characterized in that: In step (3), the nonionic surfactant in the nonionic surfactant solution includes one or more of PEG1000, PEG2000, PEG4000 and PEG6000; the mass of the nonionic surfactant in the nonionic surfactant solution is 1-10% of the mass of yttrium oxide in step (1).

4. The industrial preparation method of nano yttrium oxide for electronic ceramics according to claim 1, characterized in that: In step (4), the temperature of the heating and stirring is 20-80° C., and the stirring speed of the heating and stirring is 100-500 rap / min.

5. The industrial preparation method of nano yttrium oxide for electronic ceramics according to claim 1, characterized in that: In step (4), the aging time is 0.5-3 hours; the drying temperature is 40-150° C., and the drying time is 5-120 minutes.

6. The industrial preparation method of nano yttrium oxide for electronic ceramics according to claim 1, characterized in that: In step (4), the calcination temperature is 600-900°C and the calcination time is 0.5-5h.

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