Preparation method of high-purity superfine yttrium oxide

Abstract

This invention provides a method for preparing high-purity ultrafine yttrium oxide, relating to the field of ultrafine oxide powder preparation technology. The method involves removing impurities from a 5N-6N grade yttrium chloride solution to obtain a yttrium chloride solution with low non-rare earth impurities. While emulsifying and shearing an ammonia solution, the low-non-rare earth impurity yttrium chloride solution is introduced into the solution via atomization until the pH of the resulting solution reaches 8-10, yielding a yttrium hydroxide colloidal solution. While emulsifying and shearing the yttrium hydroxide colloidal solution, an oxalic acid solution is introduced into the solution via atomization until the pH of the resulting solution reaches 1.8-2.5. The solution is then filtered to obtain ammonium oxalate yttrium precipitate. Finally, calcination yields high-purity ultrafine yttrium oxide powder. This invention can prepare high-purity ultrafine yttrium oxide with a purity of 99.999-99.9999%, D... 50 The diameter is 0.3–0.5 μm, D 90 With a diameter of less than 1.0 μm, it is suitable for applications such as transparent ceramics and electronic ceramics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superfine oxide powder preparation, and particularly relates to a preparation method of high-purity superfine yttrium oxide. BACKGROUND

[0002] Yttrium oxide has a wide range of applications in the industries and high-tech fields of luminescent materials, laser materials, high-temperature superconducting materials, precision ceramic materials and catalyst materials. Superfine and high-purity yttrium oxide particles can significantly improve the performance and value of products.

[0003] For example, yttrium oxide required by large-size transparent ceramics pursues low non-rare earth impurity content, superfine particle size and high dispersibility, because scattering caused by trace impurities will significantly reduce the light transmittance of the final product, and only high-purity superfine powder with high sintering activity can obtain high-performance and high-density transparent ceramics through sintering. However, the lack of efficient high-purity superfine oxide preparation technology has become one of the bottlenecks of yttrium product high-quality.

[0004] Oxalic acid precipitation process is a commonly used method for preparing high-purity yttrium oxide due to its low impurity content and easy operation. However, the traditional oxalic acid precipitation process has the problems of slow nucleation of the oxalate crystal nucleus, fast growth speed, and difficulty in fine control of the physical characteristics of the reaction product due to the small ionization constant of oxalate. In recent years, there have been reports on the preparation of yttrium oxide by ammonia precipitation-oxalic acid secondary precipitation conversion. For example, Chinese patent CN201510032935.2 adjusts the particle size of yttrium hydroxide colloid by adding a surfactant, and then converts the yttrium hydroxide colloid into yttrium oxalate precipitate to obtain yttrium oxide powder with a particle size of 1-2 μm. Baoxinjun et al. (“Preparation and Formation Mechanism of Size and Morphology Controllable Y(NH4)(C2O4)·2H2O and Y2O3”, Rare Metal, October 2017, Vol. 41, No. 10) adopted ammonia-oxalic acid conversion precipitation, and under the action of dispersant polyethylene glycol (PEG2000) and surfactant sodium dodecyl benzene sulfonate (SDBS), a small volume of Y(NO3)3 solution with a certain concentration was added into a large volume of ammonia-nitrate mixed solution to form Y(OH)3 sol, and then ammonium yttrium oxalate precursor was obtained by oxalic acid conversion, and D 50 less than 1.0 μm yttrium oxide powder was obtained after calcination. However, the introduction of sodium dodecyl benzene sulfonate in the process will cause the increase of Na content in the yttrium oxide, and ammonium nitrate is also a primary hazardous chemical product prone to explosion, which is not easy to apply to industrial production.

[0005] At present, there is an urgent need for D 50 less than 0.5 μm high-purity yttrium oxide preparation process which still lacks further research. SUMMARY

[0006] In view of the above, the present application aims to provide a method for preparing high-purity ultrafine yttrium oxide. 50 The method provided by the present application can prepare high-purity (purity 99.999-99.9999%) ultrafine (median particle size D

[0007] To achieve the above-mentioned application purposes, the present application provides the following technical solutions.

[0008] The present application provides a method for preparing high-purity ultrafine yttrium oxide, comprising the following steps:

[0009] (1) removing non-rare earth impurities from a yttrium chloride solution to obtain a low-non-rare earth impurity yttrium chloride solution; the yttrium chloride solution is a 5N-6N grade yttrium chloride solution;

[0010] (2) while emulsifying and shearing the ammonia solution, the low-non-rare earth impurity yttrium chloride solution is introduced into the ammonia solution in the form of atomization until the pH value of the obtained solution is 8-10, to obtain a yttrium hydroxide colloidal solution;

[0011] (3) while emulsifying and shearing the yttrium hydroxide colloidal solution, an oxalic acid solution is introduced into the yttrium hydroxide colloidal solution in the form of atomization until the pH value of the obtained solution is 1.8-2.5, and the yttrium ammonium oxalate precipitate is obtained after filtration and washing;

[0012] (4) the yttrium ammonium oxalate precipitate is calcined to obtain high-purity ultrafine yttrium oxide powder.

[0013] Preferably, the non-rare earth impurities in step (1) include Fe elements, Al elements and Si elements, and the method for removing non-rare earth impurities comprises the following steps:

[0014] The ammonia solution is added into the yttrium chloride solution until the pH value is 4.5, then the hydrogen peroxide solution and the flocculating agent are sequentially added into the obtained solution, and the low-non-rare earth impurity yttrium chloride solution is obtained after filtration.

[0015] Preferably, the concentration of the low-non-rare earth impurity yttrium chloride solution in step (2) is 1.0-2.5 mol / L, and the temperature is 50-80℃.

[0016] Preferably, the concentration of the ammonia solution in step (2) is 1.5-3.5 mol / L, and the temperature is 40-60℃.

[0017] Preferably, the concentration of the oxalic acid solution in step (3) is 2.0-4.0 mol / L, and the temperature is 70-100℃.

[0018] Preferably, the atomized feeding in the steps (2) and (3) is carried out by a single or multiple atomizing nozzles connected with a pressure pump.

[0019] Preferably, the size of the feeding droplets formed by the atomized feeding in the steps (2) and (3) is independently 10-100 μm.

[0020] Preferably, the feeding rate of the atomized feeding in the steps (2) and (3) is independently 200-10000 mL / min.

[0021] Preferably, the shearing rate of the emulsification shearing in the steps (2) and (3) is independently 1500-8000 r / min.

[0022] Preferably, the purity of the high-purity superfine yttrium oxide powder in the step (4) is 99.999%-99.9999%, the median particle size D 50 is 0.3-0.5 μm, and D 90 is less than 1.0 μm.

[0023] The present application provides a method for preparing high-purity superfine yttrium oxide, comprising the following steps: (1) removing non-rare earth impurities from a yttrium chloride solution to obtain a low-non-rare earth impurity yttrium chloride solution; the yttrium chloride solution is a 5N-6N grade yttrium chloride solution; (2) while emulsification shearing of an ammonia solution, the low-non-rare earth impurity yttrium chloride solution is fed into the ammonia solution in the form of atomized feeding until the pH value of the obtained solution is 8-10, to obtain a yttrium hydroxide colloidal solution; (3) while emulsification shearing of the yttrium hydroxide colloidal solution, an oxalic acid solution is fed into the yttrium hydroxide colloidal solution in the form of atomized feeding until the pH value of the obtained solution is 1.8-2.5, and after filtration and washing, a yttrium ammonium oxalate precipitate is obtained; (4) the yttrium ammonium oxalate precipitate is calcined to obtain a high-purity superfine yttrium oxide powder. The present application directly uses a 5N-6N grade yttrium chloride solution (obtained by extraction separation) as raw material, which is low in cost; the present application feeds by atomization, the liquid droplets are small and uniform, the contact area of the reactants (yttrium chloride and ammonia solution, and oxalic acid solution and yttrium hydroxide colloidal solution) is large, and the shearing emulsification can effectively improve the uniformity of the micro-zone reaction in the liquid phase, reduce the generation of agglomerates, and obtain superfine yttrium oxide powder after calcination; meanwhile, the atomized feeding mode can realize large flow and high rate feeding, and the precipitation rate is fast. The method provided by the present application can prepare high-purity superfine yttrium oxide, the purity of the obtained yttrium oxide particles is 99.999%-99.9999%, the content of non-rare earth impurities is low, the uniform dispersibility is good, the median particle size D 50 is 0.3-0.5 μm, and D 90 is less than 1.0 μm, and the particle size distribution is narrow. The preparation method provided by the present application is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 XRD pattern of the ammonium yttrium oxalate precursor prepared in Example 1 and high-purity superfine yttrium oxide powder;

[0025] Figure 2 Scanning electron microscope (SEM) photos of the ammonium yttrium oxalate precursor prepared in Example 1 and high-purity superfine yttrium oxide powder, Figure 2 (a) corresponds to the ammonium yttrium oxalate precursor, and (b) corresponds to the high-purity superfine yttrium oxide powder;

[0026] Figure 3 Laser particle size test results of the high-purity superfine yttrium oxide powder prepared in Example 1. DETAILED DESCRIPTION

[0027] The present application provides a preparation method of high-purity superfine yttrium oxide, comprising the following steps:

[0028] (1) removing non-rare earth impurities from a yttrium chloride solution to obtain a low-non-rare earth impurity yttrium chloride solution; the yttrium chloride solution is a 5N-6N grade yttrium chloride solution;

[0029] (2) while emulsifying and shearing the ammonia solution, the low-non-rare earth impurity yttrium chloride solution is introduced into the ammonia solution in the form of atomization until the pH value of the obtained solution is 8-10, to obtain a yttrium hydroxide colloidal solution;

[0030] (3) while emulsifying and shearing the yttrium hydroxide colloidal solution, oxalic acid solution is introduced into the yttrium hydroxide colloidal solution in the form of atomization until the pH value of the obtained solution is 1.8-2.5, and the ammonium yttrium oxalate precipitate is obtained after filtration and washing;

[0031] (4) the ammonium yttrium oxalate precipitate is calcined to obtain high-purity superfine yttrium oxide powder.

[0032] In the present application, the yttrium chloride solution is a 5N-6N grade yttrium chloride solution, and the 5N-6N grade means that the mass percentage of yttrium element in the total rare earth elements in the yttrium chloride solution is 99.999%-99.9999%. In the present application, the 5N-6N grade yttrium chloride solution is obtained by extraction separation (a conventional technique in the art). In the examples of the present application, the 5N-6N grade yttrium chloride solution is from Ganzhou Rare Earth Longnan Smelting and Separation Company.

[0033] In the present application, the non-rare earth impurities preferably include Fe element, Al element and Si element, and the method for removing the non-rare earth impurities preferably comprises the following steps: adding an ammonia water solution into the yttrium chloride material solution to a pH value of 4.5, then sequentially adding a hydrogen peroxide solution and a flocculant into the obtained material solution, and obtaining the low non-rare earth impurity yttrium chloride material solution through filtration.

[0034] In the present application, the mass fraction of the ammonia water solution is preferably 10%, the mass fraction of the hydrogen peroxide solution is preferably 30%, and the dosage ratio of the yttrium chloride material solution to the hydrogen peroxide solution is preferably 1L:3mL. In the present application, the flocculant is preferably polyethylene oxide, and the mass of the flocculant is preferably 0.03% of the mass of the yttrium chloride material solution. In the present application, after adding the hydrogen peroxide solution, Fe 2+ in the yttrium chloride material solution is oxidized into Fe 3+ , and most of Fe 2+ , Al 3+ and Si 4+ in the material solution form Fe(OH)3, Al(OH)3 and silicic acid. The flocculant is added to make the formed colloid flocculate, and the low non-rare earth impurity yttrium chloride material solution is obtained through filtration.

[0035] After obtaining the low non-rare earth impurity yttrium chloride material solution, the present application introduces the low non-rare earth impurity yttrium chloride material solution into the ammonia water solution in the form of atomization feeding while emulsifying and shearing the ammonia water solution, until the pH value of the obtained solution is 8-10, and a yttrium hydroxide colloidal solution is obtained. In the present application, the concentration (i.e. the concentration of yttrium element) of the low non-rare earth impurity yttrium chloride material solution is preferably 1.0-2.5mol / L; when the concentration of the low non-rare earth impurity yttrium chloride material solution does not meet the range value, water needs to be added to prepare it to meet the required concentration. In the present application, the temperature of the non-rare earth impurity yttrium chloride material solution is preferably 50-80℃, more preferably 60-70℃, and further preferably 65℃. In the present application, the concentration of the ammonia water solution is preferably 1.5-3.5mol / L, more preferably 2.0-3.0mol / L, and the temperature of the ammonia water solution is preferably 40-60℃, more preferably 50-55℃.

[0036] In the present application, the size of the feed liquid droplets formed by the atomized feed is preferably 10-100 μm, the yttrium chloride feed solution is introduced into the aqueous ammonia solution in the form of fine liquid droplets by atomized feed; the feed rate of the atomized feed is preferably 200-10000 mL / min. In the present application, the atomized feed is preferably carried out by a single or multiple parallel atomizing nozzles, the atomizing nozzles are connected to a pressure pump, and the atomization is preferably electric atomization. The feed pressure can be adjusted by the pressure pump, and the atomizing nozzle with a suitable pore size is selected to adjust the feed liquid droplet size to meet the above-mentioned droplet size range; the present application can also adjust the feed rate of the atomized feed according to the volume of the reaction vessel by adjusting the number of parallel atomizing nozzles, for example, the suitable feed rate for a 5L reaction vessel is 200-300 mL / min, the suitable feed rate for a 100L reaction vessel is 1000-3000 mL / min, and the suitable feed rate for a 1000L reaction vessel is 3000-10000 mL / min.

[0037] In the present application, the shear rate of the emulsification shearing is preferably 1500-8000 r / min, and the emulsification shearing is carried out by using an emulsification shearing machine.

[0038] In the present application, the pH value of the yttrium hydroxide colloidal solution is controlled to be 8-10, preferably 8.5-9.5, and further preferably 8.7-8.8, only when the pH value of the yttrium hydroxide colloidal solution is in the range, can the D 50 The ultrafine yttrium oxide is 0.3-0.5 μm.

[0039] After obtaining the yttrium hydroxide colloidal solution, the present application introduces the oxalic acid solution into the yttrium hydroxide colloidal solution in the form of atomization feeding while shearing the solution, until the pH value of the obtained solution is 1.8-2.5 (preferably 2.0), and then the yttrium ammonium oxalate precipitate (also referred to as yttrium ammonium oxalate precursor) is obtained through filtration and washing. In the present application, the concentration of the oxalic acid solution is preferably 2.0-4.0 mol / L, more preferably 3.0 mol / L, and the temperature of the oxalic acid solution is preferably 70-100 ℃, more preferably 75-85 ℃. In the present application, the conditions of the atomization feeding are preferably the same as those in the above technical solution, which will not be described here. In the present application, the shearing rate of the shearing is preferably 1500-8000 r / min, more preferably 1500-6000 r / min. The present application does not have special requirements for the filtration mode, and the filtration mode well known to those skilled in the art can be used, such as plate and frame filter pressing. In the present application, the washing is preferably water washing, and the number of water washing is preferably 3 times. The washing is preferably followed by drying, and the temperature of the drying is preferably 120 ℃, and the time of the drying is preferably 12 h. In the present application, because excess ammonia water participates in the conversion and precipitation reaction of oxalic acid on the yttrium hydroxide colloid, the yttrium ammonium oxalate is formed.

[0040] After obtaining the yttrium ammonium oxalate precipitate, the present application calcines the yttrium ammonium oxalate precipitate to obtain high-purity ultrafine yttrium oxide powder. In the present application, the temperature of the calcination is preferably 950 ℃, and the time of the calcination is preferably 2 h. After the calcination, the temperature is cooled to room temperature.

[0041] In the present application, the purity of the high-purity ultrafine yttrium oxide powder is 99.999%-99.9999%, the median particle size D 50 is 0.3-0.5 μm, and D 90 is less than 1.0 μm.

[0042] The present application uses the atomization feeding mode to effectively control the droplet size of the precursor solution under the premise of ensuring large flow rate and high rate of feeding, and the shearing emulsification is used to improve the uniformity of the precipitation reaction, and the pH value of the yttrium hydroxide colloidal solution is strictly controlled to obtain high-purity ultrafine yttrium oxide powder. The high-purity ultrafine yttrium oxide powder has low content of non-rare earth impurities, and is suitable for transparent ceramics, electronic ceramics and other fields.

[0043] In order to further illustrate the present application, the preparation method of high-purity ultrafine yttrium oxide provided by the present application is described in detail below with examples, but they should not be understood as limiting the scope of protection of the present application.

[0044] Example 1

[0045] A 100-L reactor was used as the reaction vessel, and 1.35 mol / L 5N yttrium chloride solution obtained by extraction separation was used as the raw material (denoted as yttrium chloride solution A). 10% ammonia solution was added to 40 L of the yttrium chloride solution A until the pH value was 4.5, 120 mL of hydrogen peroxide solution (30 wt%) was added, flocculating agent (12 g of polyethylene oxide dissolved in 2 L of pure water) was added to flocculate the colloid, and filtration was performed to obtain a low non-rare earth impurity yttrium chloride solution (denoted as yttrium chloride solution B, 1.0 mol / L). 30 L of the 65℃ yttrium chloride solution B was introduced into 3.0 mol / L ammonia solution at 55℃ at a rate of 2 L / min by means of electric atomization, and a yttrium hydroxide colloidal solution with a pH value of 8.8 was obtained by reaction under the action of emulsification shearing (2800 r / min);

[0046] 3.0 mol / L oxalic acid solution at 75℃ was introduced into the above-mentioned yttrium hydroxide colloidal solution at a rate of 2 L / min by means of electric atomization, and yttrium ammonium oxalate was generated by reaction under the action of emulsification shearing (2800 r / min) until the pH value of the mixed solution containing the yttrium ammonium oxalate precipitate was 2.0, and a mixed solution containing the yttrium ammonium oxalate precipitate was obtained.

[0047] The mixed solution containing the yttrium ammonium oxalate precipitate was subjected to plate-and-frame pressure filtration to obtain yttrium ammonium oxalate precursor, the precursor was washed with deionized water for 3 times, was dried after being pumped dry, was baked at 120℃ for 12 h, was calcined at 950℃ for 2 h, was cooled to room temperature, and D 50 high-purity superfine yttrium oxide powder with D 90 0.80 μm was obtained.

[0048] The purity and impurity content of the yttrium chloride solution used in Example 1 are shown in Table 1:

[0049] Table 1 Purity and impurity content of yttrium chloride solution

[0050]

[0051] Figure 1 The XRD patterns of the yttrium ammonium oxalate precursor and the high-purity superfine yttrium oxide powder obtained in Example 1.

[0052] Figure 2 The scanning electron microscope (SEM) photos of the yttrium ammonium oxalate precursor and the high-purity superfine yttrium oxide powder obtained in Example 1, Figure 2 wherein (a) corresponds to the yttrium ammonium oxalate precursor, and (b) corresponds to the high-purity superfine yttrium oxide powder. It can be seen from Figure 2 that the yttrium ammonium oxalate precursor is granular, and the yttrium oxide after calcination is a block structure composed of spherical grains, and the block size is between 200-500 nm.

[0053] Figure 3The laser particle size test results of the high-purity ultrafine yttrium oxide powder prepared in Example 1 are shown in Table 2.

[0054] The main non-rare earth impurity contents of the high-purity ultrafine yttrium oxide powder prepared in Example 1 are shown in Table 3:

[0055] Table 3 Main non-rare earth impurity contents of the high-purity ultrafine yttrium oxide powder prepared in Example 1

[0056]

[0057] Example 2

[0058] The yttrium chloride solution B was obtained in the same way as in Example 1.

[0059] The 500 mL yttrium chloride solution B at 65°C was introduced into the 3.0 mol / L ammonia solution at 55°C at a rate of 200 mL / min by means of electric atomization in a 3 L beaker, and a yttrium hydroxide colloidal solution with a pH value of 8.7 was obtained under the emulsification shearing action (6000 r / min);

[0060] The 3.0 mol / L oxalic acid solution at 75°C was introduced into the above-mentioned yttrium hydroxide colloidal solution at a rate of 200 mL / min by means of electric atomization, and yttrium ammonium oxalate was generated under the emulsification shearing action (6000 r / min) until the pH value of the mixed solution containing the yttrium ammonium oxalate precipitate was 2.0, and a mixed solution containing the yttrium ammonium oxalate precipitate was obtained.

[0061] The mixed solution containing the yttrium ammonium oxalate precipitate was filtered to obtain the yttrium ammonium oxalate precursor, which was washed with deionized water for 3 times, and then dried at 80°C for 12 h after being sucked dry, and then calcined at 950°C for 2 h, and then cooled to room temperature to obtain the high-purity ultrafine yttrium oxide powder.

[0062] The laser particle size test results of the high-purity ultrafine yttrium oxide powder prepared in Example 2 are shown in Table 2.

[0063] Comparative Example 1

[0064] The yttrium chloride solution B was obtained in the same way as in Example 1.

[0065] The 500 mL yttrium chloride solution B at 65°C was introduced into the 3.0 mol / L ammonia solution at 55°C at a rate of 200 mL / min by means of peristaltic pump, and a yttrium hydroxide colloidal solution with a pH value of 8.7 was obtained under the emulsification shearing action (6000 r / min);

[0066] The 3.0 mol / L oxalic acid solution at 75℃ was passed into the above yttrium hydroxide colloidal solution at a rate of 200 mL / min by using a peristaltic pump, and under the emulsification shearing (6000 r / min) to react to generate yttrium ammonium oxalate until the pH value of the mixed solution containing the yttrium ammonium oxalate precipitate was 2.0, to obtain the mixed solution containing the yttrium ammonium oxalate precipitate;

[0067] The mixed solution containing the yttrium ammonium oxalate precipitate was filtered to obtain the yttrium ammonium oxalate precursor, the precursor was washed with deionized water for 3 times, and after being dried, it was dried at 80℃ for 12 h, and then calcined at 950℃ for 2 h, and cooled to room temperature to obtain the yttrium oxide powder.

[0068] The laser particle size test results of the yttrium oxide powder prepared in Comparative Example 1 are shown in Table 2.

[0069] Comparative Example 2

[0070] The yttrium chloride solution B was obtained in the same manner as in Example 1.

[0071] The 500 mL yttrium chloride solution B at 65℃ was passed into the 3.0 mol / L ammonia solution at 55℃ at a rate of 200 mL / min by using a peristaltic pump, and under the mechanical stirring (1500 r / min) to react to obtain the yttrium hydroxide colloidal solution with a pH value of 8.7;

[0072] The 3.0 mol / L oxalic acid solution at 75℃ was passed into the above yttrium hydroxide colloidal solution at a rate of 200 mL / min by using a peristaltic pump, and under the mechanical stirring (1500 r / min) to react to generate yttrium ammonium oxalate until the pH value of the mixed solution containing the yttrium ammonium oxalate precipitate was 2.0, to obtain the mixed solution containing the yttrium ammonium oxalate precipitate;

[0073] The mixed solution containing the yttrium ammonium oxalate precipitate was filtered to obtain the yttrium ammonium oxalate precursor, the precursor was washed with deionized water for 3 times, and after being dried, it was dried at 80℃ for 12 h, and then calcined at 950℃ for 2 h, and cooled to room temperature to obtain the yttrium oxide powder.

[0074] The laser particle size test results of the yttrium oxide powder prepared in Comparative Example 2 are shown in Table 2.

[0075] The particle size results of Comparative Examples 1 and 2 show that under the same conditions of feeding rate, reaction temperature, concentration, and end point pH value, the emulsification shearing can obtain finer yttrium oxide powder than the conventional stirring, and at the same time, the atomization feeding and emulsification shearing can further improve the precipitation uniformity, and obtain the ultrafine yttrium oxide powder with finer particle size and narrower particle size distribution.

[0076] Comparative Example 3

[0077] The yttrium chloride solution B was obtained in the same manner as in Example 1.

[0078] The 500 mL yttrium chloride solution B at 65℃ is introduced into the 3.0 mol / L ammonia solution at 55℃ at a rate of 200 mL / min in an electric atomization mode, and a yttrium hydroxide colloidal solution with a pH value of 7.8 is obtained under the emulsification shearing action (6000 r / min);

[0079] The 3.0 mol / L oxalic acid solution at 75℃ is introduced into the above-mentioned yttrium hydroxide colloidal solution at a rate of 200 mL / min in an electric atomization mode, and yttrium ammonium oxalate is generated under the emulsification shearing action (6000 r / min) until the pH value of the mixed solution containing the yttrium ammonium oxalate precipitate is 2.0, and the mixed solution containing the yttrium ammonium oxalate precipitate is obtained;

[0080] The mixed solution containing the yttrium ammonium oxalate precipitate is filtered to obtain the yttrium ammonium oxalate precursor, the precursor is washed with deionized water for 3 times, is dried by suction, and is dried at 80℃ for 12 h, and is calcined at 950℃ for 2 h, and is cooled to room temperature to obtain the high-purity superfine yttrium oxide powder.

[0081] The laser particle size test results of the yttrium oxide powder prepared in the above-mentioned Comparative Example 3 are shown in Table 2.

[0082] Table 2 Laser particle size test results of the yttrium oxide powder of the examples and the comparative examples

[0083]

[0084] The above-mentioned only is the preferred embodiment of the present application, and does not limit the present application in any form. It should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for preparing high-purity ultrafine yttrium oxide, characterized in that, The method comprises the following steps: (1) removing non-rare earth impurities from a yttrium chloride solution to obtain a low non-rare earth impurity yttrium chloride solution; the yttrium chloride solution is a 5N-6N grade yttrium chloride solution; (2) while emulsifying and shearing an ammonia solution, the low non-rare earth impurity yttrium chloride solution is introduced into the ammonia solution in the form of atomized feed until the pH value of the obtained solution is 8-10, thereby obtaining a colloidal yttrium hydroxide solution; (3) while emulsifying and shearing the colloidal yttrium hydroxide solution, an oxalic acid solution is introduced into the colloidal yttrium hydroxide solution in the form of atomized feed until the pH value of the obtained solution is 1.8-2.5, and the obtained solution is filtered and washed to obtain a yttrium ammonium oxalate precipitate; (4) the yttrium ammonium oxalate precipitate is calcined to obtain high-purity ultrafine yttrium oxide powder.

2. The production method according to claim 1, characterized by, The non-rare earth impurities in step (1) include Fe elements, Al elements and Si elements, and the method for removing the non-rare earth impurities comprises the following steps: ammonia solution is added to the yttrium chloride solution until the pH value is 4.5, then hydrogen peroxide solution and flocculants are sequentially added to the obtained solution, and the obtained solution is filtered to obtain the low non-rare earth impurity yttrium chloride solution.

3. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the low non-rare earth impurity yttrium chloride solution is 1.0-2.5 mol / L, and the temperature is 50-80°C.

4. The production method according to claim 1, characterized by, In step (2), the concentration of the ammonia solution is 1.5-3.5 mol / L, and the temperature is 40-60°C.

5. The method of claim 1, wherein, In step (3), the concentration of the oxalic acid solution is 2.0-4.0 mol / L, and the temperature is 70-100°C.

6. The method of claim 1, wherein, The atomized feed in steps (2) and (3) is introduced through a single or multiple atomizing nozzles connected to a pressure pump.

7. The production method according to claim 1 or 6, characterized by, The size of the feed droplets formed by the atomized feed in steps (2) and (3) is independently 10-100 μm.

8. The production method according to claim 1 or 6, characterized by, The feed rate of the atomized feed in steps (2) and (3) is independently 200-10000 mL / min.

9. The method of claim 1, wherein, The shearing rate of the emulsification and shearing in steps (2) and (3) is independently 1500-8000 r / min.

10. The method of claim 1, wherein, The purity of the high-purity superfine yttrium oxide powder in the step (4) is 99.999% to 99.9999%, the median particle size D 50 is 0.3 to 0.5 μm, and D 90 is less than 1.0 μm.

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