Industrial preparation method for nano-yttrium oxide for electronic ceramics

Abstract

To provide an industrial preparation method of nano yttrium oxide for electronic ceramics, wherein the nano yttrium oxide is nano-sized, has a high specific surface area, is easily dispersible, and is suitable for the electronic ceramics industry.SOLUTION: First, yttrium oxide is dissolved in nitric acid to remove anionic impurities from the yttrium oxide, then impurities are further removed using a (NH4)2S solution to obtain a high-purity yttrium nitrate solution, and two-stage precipitation is carried out using ammonia water and an ammonium hydrogen carbonate solution to obtain yttrium carbonate crystals, and finally, calcination and decomposition are carried out to obtain nano yttrium oxide for electronic ceramics.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an industrial method for preparing nano-yttrium oxide for electronic ceramics. [Background technology]

[0002] Nano-yttrium oxide powder is an important raw material for electronic ceramics. It belongs to the cubic crystal system, exhibits excellent high-temperature stability, good heat and corrosion resistance, a melting point exceeding 2400°C, and a dielectric constant of 12-20. Nano-yttrium oxide powder is a novel, high-performance, precision inorganic electronic material widely applied in fields such as aerospace, nuclear energy, and high-tech ceramics. These fields require yttrium oxide powder with finer particle size, more uniform particle size distribution, good dispersibility, and sintering activity. Currently, it is possible to industrially prepare Y2O3 powder with a purity of 99.99% or 99.999% using ion exchange or solvent extraction methods. However, the sintering activity of industrially prepared powders does not yet fully meet the requirements for yttrium oxide powder in the aforementioned fields. Therefore, researching methods for preparing ultrafine yttrium oxide powder with simple production processes, low production costs, controllable particle size, and high activity is of paramount importance.

[0003] Conventional methods for preparing fine-grained yttrium oxide powder include precipitation, sol-gel, gas-phase deposition, microemulsion, and hydrothermal methods. Precipitation methods include oxalic acid precipitation, carbonate precipitation, hydroxide precipitation, homogeneous precipitation, and complex precipitation. These precipitation methods are characterized by rapid nucleation in solution, easy control, simple equipment, and the ability to obtain high-purity products, but they are difficult to filter and prone to aggregation. The hydrothermal method refers to a process that promotes the hydrolysis reaction of ions under high temperature and high pressure conditions to form dispersed nanocrystalline nuclei. This method can produce nanopowder with uniform dispersion and a narrow particle size distribution, but it requires high-temperature and high-pressure equipment, is expensive, has low production efficiency, and low work safety. The gel method refers to a process in which organometallic compounds or organic complexes form a sol at low temperatures through polymerization or hydrolysis reactions, then gel under specific conditions, and further heat treatment is performed to obtain ultrafine nanopowder with a large specific surface area and good dispersibility. This method can be carried out under mild conditions, and the resulting powder has a large specific surface area and good dispersibility. However, the reaction time is long, taking several days to complete, making it difficult to meet the demands of large-scale industrialization. The solid-phase method refers to a process that obtains ultrafine powder by performing high-temperature decomposition through the reaction of a solid compound or intermediate (for example, solid-phase mixing of a rare earth salt with oxalic acid or ammonium carbonate to form a rare earth salt intermediate, and then decomposing it at high temperature). This method has high reaction efficiency, simple equipment, and is easy to operate, but the resulting powder has an irregular shape and low uniformity.

[0004] Therefore, providing an industrial preparation method for nano-yttrium oxide for electronic ceramics that has fine particle size, high purity, and high specific surface area is a technical challenge that engineers in this field must address immediately. [Overview of the project]

[0005] The present invention aims to provide an industrial method for preparing nano-yttrium oxide for electronic ceramics, which is characterized by fine particle size, high purity, and high specific surface area.

[0006] To achieve the above objective, the present invention provides the following technical solutions.

[0007] In one embodiment, the present invention is An industrial method for preparing nano-yttrium oxide for electronic ceramics, Step (1): Dissolve yttrium oxide in a nitric acid solution to obtain a first yttrium nitrate solution. Step (2) involves mixing the first yttrium nitrate solution obtained in step (1) with the (NH4)2S solution, and heating and stirring to obtain a second yttrium nitrate solution. Step (3) involves adding ammonia water to the nonionic surfactant solution obtained in step (2) to the second yttrium nitrate solution, and then adding ammonia water to obtain a suspension. Step (4) involves adding the ammonia bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, and then undergoing aging, filtration, washing, drying and firing to obtain the nano-yttrium oxide for electronic ceramics. This invention provides an industrial method for preparing nano-yttrium oxide for electronic ceramics, including [specific components / methods].

[0008] According to the preparation method of the present invention, preferably, in step (1), the concentration of the yttrium nitrate solution is 50 to 200 g / L.

[0009] According to the preparation method of the present invention, preferably in step (2), the concentration of the (NH4)2S solution is 10 to 200 g / L, and the mass of (NH4)2S in the (NH4)2S solution is 0.1 to 1% of the mass of yttrium oxide used in step (1).

[0010] According to the preparation method of the present invention, preferably in step (3), the nonionic surfactant in the nonionic surfactant solution is one or more selected from PEG1000, PEG2000, PEG4000, and PEG6000, and the mass of the nonionic surfactant in the nonionic surfactant solution is 1 to 10% of the mass of yttrium oxide used in step (1).

[0011] According to the preparation method of the present invention, preferably in step (3), the amount of ammonia water used is controlled so that the concentration of the ammonia water is 10 to 25% and the pH value is adjusted to 5 to 6.

[0012] According to the preparation method of the present invention, preferably in step (4), the amount of ammonium bicarbonate solution used is controlled so that the concentration of the ammonium bicarbonate solution is 50 to 300 g / L, the dropping rate of the ammonium bicarbonate solution is 0.01 to 10 L / h, and the pH value of the suspension is adjusted to 7.8.

[0013] According to the preparation method of the present invention, preferably, in the heating and stirring process of step (4), the temperature is 20 to 80°C and the stirring speed is 100 to 500 raps / min.

[0014] According to the preparation method of the present invention, preferably in step (4), the maturation time is 0.5 to 3 hours, the drying temperature is 40 to 150°C, and the drying time is 5 to 120 minutes.

[0015] According to the preparation method of the present invention, preferably in step (4), the firing temperature is 600 to 900°C and the firing time is 0.5 to 5 hours.

[0016] In another aspect, the present invention further provides nano-yttrium oxide for electronic ceramics obtained by the preparation method described above.

[0017] In the present invention, first, yttrium oxide is dissolved in nitric acid, and anion impurities are removed from the yttrium oxide to obtain a first yttrium nitrate solution. Then, an (NH4)2S solution is used to further remove impurities, so as to obtain a high-purity yttrium nitrate solution (a second yttrium nitrate solution). Then, two-stage precipitation is performed using ammonia water and an ammonium bicarbonate solution to obtain yttrium carbonate crystals, and finally, calcination decomposition is performed to obtain nano yttrium oxide for electronic ceramics. The yttrium oxide obtained by the present invention is nano-sized, has a high specific surface area, is easy to disperse, and is suitable for the electronic ceramic industry. The method according to the present invention is suitable for industrial production and has broad application prospects.

[0018] The present invention synthesizes yttrium carbonate crystals by using an ammonia water-ammonium bicarbonate two-stage precipitation method, and has the characteristics of easy filtration, easy impurity cleaning, etc. The yttrium oxide powder obtained after calcination has small particle size, uniform size distribution, no hard agglomeration, good looseness and good dispersibility. The method according to the present invention is low in cost and easy to industrialize.

[0019] [Mode for Carrying Out the Invention] Hereinafter, the technical solutions of the embodiments of the present invention will be described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those skilled in the art without creative efforts based on the embodiments of the present invention shall all fall within the protection scope of the present invention.

[0020] In order to make the above objects, features and advantages of the present invention easier to understand clearly, the present invention will be further described in detail below with reference to specific embodiments.

[0021] The industrial preparation method of nano yttrium oxide for electronic ceramics according to the present invention comprises the following steps.

[0022] Step (1): A step of dissolving yttrium oxide in a nitric acid solution to obtain a yttrium nitrate solution, wherein a yttrium nitrate solution with a specific concentration can be obtained by dilution with water as needed, and the obtained yttrium nitrate solution is defined as a first yttrium nitrate solution Step (2): A step of mixing the yttrium nitrate solution obtained in step (1) with a (NH4)2S solution, and heating and stirring the mixture to obtain a high-purity yttrium nitrate solution, wherein for distinction, the high-purity yttrium nitrate solution is defined as a second yttrium nitrate solution, and "high-purity" means that the second yttrium nitrate solution has a lower impurity content than the first yttrium nitrate solution Step (3): A step of 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; and Step (4): A step of adding an ammonium bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, then performing aging, filtration, washing, drying and calcination to obtain the nano yttrium oxide for electronic ceramics In step (1), the concentration of the yttrium nitrate solution may be 50~200g / L, preferably 80~150g / L. In conventional yttrium oxide with a purity of 99.9%, the content of impurity cations such as iron, calcium, zinc and lead, and Cl - , F - , SO4 2- and other anions exceeds the standard and does not meet the specifications for electronic ceramics. In the present invention, yttrium oxide is dissolved in a nitric acid solution to prepare a yttrium nitrate solution, and Cl - , F - , SO4 2- and other anionic impurities are removed, and the finally obtained nano yttrium oxide for electronic ceramics meets the relevant standards for anionic impurities such as Cl - , F - , SO4 2- and the like.

[0023] According to an embodiment of the present invention, in step (1), the purity of the yttrium oxide may be 99.9%.

[0024] In step (2), the concentration of the (NH4)2S solution may be 10 to 200 g / L, preferably 20 to 100 g / L. The mass of (NH4)2S in the (NH4)2S solution may be 0.1 to 1% of the mass of yttrium oxide used in step (1), preferably 0.1 to 0.5%. In this invention, impurities are further removed using the (NH4)2S solution, and the resulting high-purity yttrium nitrate solution contains CaO < 10 ppm, Fe2O3 < 10 ppm, ZnO < 10 ppm, PbO < 10 ppm, Cl - F - SO4 2- The purity is <20 ppm, which is advantageous for obtaining nano-yttrium oxide that exceeds 99.99% and conforms to the yttrium oxide standard for electronic ceramics.

[0025] According to one embodiment of the present invention, step (2) further includes mixing the yttrium nitrate solution and the (NH4)2S solution, and then adding nitric acid or yttrium oxide until the pH value is 2 to 3. In the present invention, nitric acid is H + It can provide H to adjust the pH value, and yttrium oxide is used when the pH is too low. + This can neutralize the substance and adjust the pH, thus achieving its objective.

[0026] In the heating and stirring process of step (2), the temperature may be 20 to 70°C, preferably 20 to 50°C, and the time may be 30 min.

[0027] In step (3), the nonionic surfactant in the nonionic surfactant solution may contain one or more of PEG1000, PEG2000, PEG4000, and PEG6000, preferably one or more of PEG2000, PEG4000, and PEG6000. As is well known in the art, the number after PEG represents the molecular weight. The mass of the nonionic surfactant in the nonionic surfactant solution is 1 to 10% of the mass of yttrium oxide used in step (1), preferably 1 to 5%. The nonionic surfactant of the present invention is advantageous in obtaining yttrium oxide powder with high dispersibility and a large specific surface area by encapsulating the subsequently formed yttrium carbonate crystals, preventing the growth of crystal grains, and generating a large amount of gas during the calcination process of the yttrium carbonate crystals, thereby performing a separation effect and preventing aggregation of yttrium oxide.

[0028] According to one embodiment of the present invention, in step (3), the concentration of the ammonia water may be 10 to 25%, preferably 15 to 20%. The amount of ammonia water used is controlled so that the pH value is 5 to 6. In the present invention, controlling the concentration and amount of ammonia water used within the above range is advantageous for the formation of amorphous precipitate of Y2(OH)5(NO3)·nH2O. If the concentration or amount of ammonia water used falls outside the above range, hexagonal Y(OH)3 crystals that cannot be converted to Y2(CO3)3 crystals are formed.

[0029] In step (4), the concentration of the ammonium bicarbonate solution may be 50 to 300 g / L, preferably 100 to 200 g / L. The dropping rate of the ammonium bicarbonate solution may be 0.01 to 10 L / h, preferably 0.01 to 1 L / h. The amount of ammonium bicarbonate solution used is controlled so that the pH value is 7.8. The present invention is advantageous for gradually converting the amorphous precipitate of Y2(OH)5(NO3)·nH2O to the Y2(CO3)3 crystalline form by controlling the concentration, dropping rate, and amount of ammonium bicarbonate solution within the above range. If the concentration of the ammonium bicarbonate solution falls outside the above range, the crystal grains may become larger or aggregation may occur. If the dropping rate of the ammonium bicarbonate solution falls outside the above range, the nucleation rate and growth rate of the crystal grains may change. If the amount of ammonium bicarbonate solution used falls outside the above range, the loss of rare earth elements may increase or the content of impurities may increase, making washing and filtration difficult.

[0030] This invention synthesizes yttrium carbonate crystals using a two-step ammonia-ammonium bicarbonate precipitation method, and has features such as easy filtration and easy washing of impurities. The yttrium oxide particles obtained after calcination have a small particle size, a uniform size distribution, do not form hard aggregates, are easily broken down, and have good dispersibility. The method of this invention is not only low-cost but also easily industrialized.

[0031] According to one embodiment of the present invention, in the heating and stirring process in step (4), the temperature may be 20 to 80°C, preferably 20 to 60°C, and the stirring speed may be 100 to 500 rap / min, preferably 100 to 350 rap / min. With respect to rotational speed, rap / min is synonymous with rpm.

[0032] According to one preferred embodiment of the present invention, in step (4), the maturation time may be 0.5 to 3 hours, preferably 0.5 to 2 hours. The maturation method is stirring maturation. The maturation can be carried out using equipment well known in the art, and a detailed description thereof is omitted here. The stirring maturation of the present invention is advantageous in promoting the conversion from amorphous to crystalline and in suppressing further growth of yttrium carbonate crystals.

[0033] According to one preferred embodiment of the present invention, in step (4), the reagents used for washing may be deionized water and ethanol.

[0034] According to one preferred embodiment of the present invention, in step (4), the drying temperature may be 40 to 150°C, preferably 60 to 90°C. The drying time may be 5 to 120 mins, preferably 10 to 60 mins. The present invention is advantageous in forming a yttrium oxide precursor with small particle size and no aggregation by controlling the drying temperature and time within the above ranges. If the drying temperature falls outside the above range, hard agglomeration occurs between particles, reducing the specific surface area. If the drying time falls outside the above range, aggregation of crystal grains increases, reducing the specific surface area.

[0035] According to one preferred embodiment of the present invention, in step (4), the drying method may be microwave drying. Microwave drying can be performed using equipment well known in the art, and a detailed explanation thereof is omitted here. The present invention allows for simultaneous heating of the inside and outside of the material by microwave drying, preferentially vaporizing surface moisture to form an internal pressure gradient, and rapidly evaporating internal moisture to significantly shorten the drying time. The water vapor generated when internal water molecules vaporize expands due to heat, causing the particles to split into minute fragments, increasing the specific surface area, preventing aggregation, and is advantageous in obtaining nano-yttrium oxide with small particle size and high specific surface area.

[0036] According to one preferred embodiment of the present invention, in step (4), the firing temperature may be 600 to 900°C, preferably 650 to 850°C. The firing time may be 0.5 to 5 hours, preferably 1 to 3 hours. The firing can be carried out using equipment well known in the art, and a detailed description thereof is omitted here. In the present invention, yttrium carbonate crystals are decomposed into Y2O3 by firing. The present invention is advantageous in that by controlling the firing temperature and time within the above range, the structure is stable and the crystal form is a perfect cubic yttrium oxide. If the firing temperature is outside the above range, particle diffusion increases exponentially and grain growth occurs. If the firing time is outside the above range, small crystal grains diffuse across grain boundaries into larger crystal grains, the grain boundaries move and the larger crystal grains grow further, and the small crystal grains are incorporated and disappear.

[0037] The above preparation method can yield nano-yttrium oxide for electronic ceramics.

[0038] The nano-yttrium oxide for electronic ceramics according to the present invention has a small particle size, a uniform size distribution, good dispersibility, few impurities, and a high specific surface area.

[0039] Unless otherwise specified, all raw materials used in the following examples were purchased commercially.

[0040] In the following examples, room temperature means 25±3℃.

[0041] Examples 1-4 (1) Yttrium oxide powder with a purity of 99.9% was dissolved in nitric acid to obtain a yttrium nitrate solution (first yttrium nitrate solution).

[0042] (2) The (NH4)2S solution was added to the yttrium nitrate solution obtained in step (1), and nitric acid or yttrium oxide powder was added to adjust the pH to 2-3. The mixture was heated and stirred for 30 minutes, and then filtered to obtain a high-purity yttrium nitrate solution (second yttrium nitrate solution).

[0043] (3) A nonionic surfactant was dissolved in deionized water to obtain a nonionic surfactant solution. This was then added to the high-purity yttrium nitrate solution obtained in step (2), and ammonia water was added dropwise to a pH of 5-6 to obtain a suspension.

[0044] (4) Under heating and stirring conditions, ammonium bicarbonate solution was added to the suspension obtained in step (3) until the pH reached 7.8, and yttrium carbonate crystals were obtained by stirring, maturation, and filtration. The yttrium carbonate crystals were alternately washed with deionized water and ethanol, microwave-dried in a microwave field, and then calcined in a muffle furnace to obtain nano-yttrium oxide for electronic ceramics.

[0045] The process parameters for Examples 1 to 4 are shown in Table 1.

[0046] TIFF0007918312000001.tif221170

[0047] Example 5 In step (3), the nonionic surfactant PEG4000 was replaced with PEG1000.

[0048] Otherwise, it was the same as in Example 1.

[0049] Ratio 1 In step (3), a nonionic surfactant was added to the high-purity yttrium nitrate solution obtained in step (2), and ammonia water was added dropwise to a pH of 5-6 to obtain a suspension.

[0050] Otherwise, it was the same as in Example 1.

[0051] Ratio Proportionality 2 In step (4), stirring and aging was replaced with static aging.

[0052] Otherwise, it was the same as in Example 1.

[0053] Ratio Proportionality 3 In step (5), the alternating washing with deionized water and ethanol was replaced with washing with deionized water only.

[0054] Otherwise, it was the same as in Example 1.

[0055] Ratio 4 In step (5), microwave drying in a microwave field was replaced with drying in a drying box.

[0056] Otherwise, it was the same as in Example 1.

[0057] TIFF0007918312000002.tif62170

[0058] As can be seen from Table 2, changing the method of adding nonionic surfactants, the maturation method, or the washing reagents and drying methods affects the yield, particle size, and specific surface area of ​​the Y2O3 powder.

[0059] The above are preferred embodiments of the present invention, but the technical scope of the present invention is not limited thereto. Modifications or alternatives that can be easily conceived by those skilled in the art based on the technical scope of the present invention also fall within the technical scope of the present invention. Therefore, the technical scope of the present invention is the same as the technical scope of the patent claims.

Claims

1. An industrial method for preparing yttrium oxide for electronic ceramics, Step (1) to obtain a first yttrium nitrate solution by dissolving yttrium oxide in a nitric acid solution. The first yttrium nitrate solution obtained in step (1) and (NH ４ ) ２ Step (2): Mix with solution S, heat and stir to obtain a second yttrium nitrate solution. Step (3) involves adding ammonia water to the nonionic surfactant solution obtained in step (2) to the second yttrium nitrate solution, and then adding ammonia water to obtain a suspension. Step (4) involves adding the ammonia bicarbonate solution to the suspension obtained in step (3) under heating and stirring conditions, and then proceeding through aging, filtration, washing, drying, and firing to obtain the yttrium oxide for electronic ceramics. An industrial method for preparing yttrium oxide for electronic ceramics, characterized by containing [a certain substance].

2. The method for industrially preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that the concentration of the yttrium nitrate solution in step (1) is 50 to 200 g / L.

3. In process (2), (NH ４ ) ２ The concentration of the S solution is 10-200 g / L, (NH ４ ) ２ (NH in S solution) ４ ) ２ The industrial method for preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that the mass of S is 0.1 to 1% of the mass of yttrium oxide used in step (1).

4. The method for industrially preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that in step (3), the nonionic surfactant in the nonionic surfactant solution is one or more selected from PEG1000, PEG2000, PEG4000, and PEG6000, and the mass of the nonionic surfactant in the nonionic surfactant solution is 1 to 10% of the mass of yttrium oxide used in step (1).

5. The method for industrially preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that in step (3), the concentration of the ammonia water is 10 to 25% and the amount of ammonia water used is controlled to adjust the pH value to 5 to 6.

6. The method for industrially preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that in step (4), the concentration of the sodium bicarbonate solution is 50 to 300 g / L, the dropping rate of the ammonium bicarbonate solution is 0.01 to 10 L / h, and the amount of ammonium bicarbonate solution used is controlled to adjust the pH value of the suspension to 7.

8.

7. The industrial method for preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that, in the heating and stirring process of step (4), the temperature is 20 to 80°C and the stirring speed is 100 to 500 raps / min.

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

9. The method for industrially preparing yttrium oxide for electronic ceramics according to claim 1, characterized in that in step (4), the firing temperature is 600 to 900°C and the firing time is 0.5 to 5 hours.

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