Efficient preparation method of high-purity rare earth metal oxide

Abstract

The invention relates to the technical field of rare earth oxide preparation, in particular to a high-purity rare earth metal oxide efficient preparation method which comprises the steps that rare earth metal raw materials are dissolved in ethyl alcohol, and a first solution is obtained; reacting organic acid with the first solution to generate mixed complex salt; adding oxygen aerosol into the mixed complex salt, and reacting the mixed complex salt in combination with UV light treatment to form a rare earth oxide precursor; according to the method, organic acid H2C2O4 is introduced to serve as a complex salt ligand, rare earth ions are stabilized, reaction uniformity and stability are achieved, oxygen aerosol and UV light are used for treatment, the reaction speed and product structure control are improved, a microcosmic control technology is combined, and the high-purity rare earth metal oxide is obtained. Reaction parameters and structural design are optimized, the morphology and lattice structure of the rare earth oxide are regulated and controlled, the preparation efficiency of the rare earth metal oxide is improved, and relatively high purity is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth oxide preparation, and particularly to a method for efficiently preparing high-purity rare earth metal oxides. Background Art

[0002] Rare earth oxides have important applications in the fields of materials science and engineering, such as being widely used in catalysts, electronic materials, optical materials, etc. Traditional methods for preparing rare earth oxides mostly use physical or chemical methods, but there are problems such as complex preparation processes, low product purity, and insufficient structural control.

[0003] In order to improve the preparation efficiency, purity, and structural control ability of rare earth oxides, it is necessary to conduct research and development by means of advanced reaction conditions and microscopic control technologies. Therefore, the rare earth oxide preparation technology based on oxygen aerosol and UV (ultraviolet) irradiation treatment for chemical reactions, combined with microscopic reaction control, is the current research hotspot and development direction. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for efficiently preparing high-purity rare earth metal oxides, aiming to improve the chemical reaction uniformity and stability during the preparation of rare earth metal oxides, enhance the microscopic structure control ability of the product, and efficiently obtain rare earth oxides with high purity.

[0005] To achieve the above purpose, the present invention provides a method for efficiently preparing high-purity rare earth metal oxides, including the following steps:

[0006] Dissolve the rare earth metal raw material in ethanol to obtain a first solution;

[0007] React an organic acid with the first solution to generate a mixed complex salt;

[0008] Add oxygen aerosol to the mixed complex salt, and react the mixed complex salt by combining UV light irradiation treatment to form a rare earth oxide precursor;

[0009] Perform pyrolysis treatment on the rare earth oxide precursor to obtain high-purity rare earth metal oxides.

[0010] Among them, the rare earth metal raw material is RE2(C2O4)3, the purity should reach more than 99.9%, the concentration remains 1 mol / L, and it is detected by inductively coupled plasma emission spectroscopy, and the total content of impurity elements is less than 0.1%.

[0011] Among them, the ethanol solvent is of analytical pure grade with a purity of at least 99.7%. It can be distilled and purified at 78 - 80 °C before use. To ensure the full dissolution of the rare earth metal raw material, the dosage of the ethanol solvent can be appropriately adjusted so that the mass - volume ratio of the rare earth metal raw material to the ethanol is between 1:10 - 1:15.

[0012] Among them, the organic acid is H2C2O4 with a purity of not less than 99%. The proportion of impurity peak area detected by high - performance liquid chromatography is less than 1%. It is optimized within the molar ratio range of 0.95 - 1.05:1. When the molar ratio is 1.02:1, the reaction yield can be increased by 5%.

[0013] Among them, the reaction temperature of the UV light treatment is optimized within the range of 78 - 82 °C. When the temperature is 80 °C, the reaction rate is moderate and the yield is high. At this temperature, after reacting for 1 hour, the yield of the rare earth oxide precursor can reach 70%. When the temperature rises to 82 °C, the reaction rate accelerates, but the side reactions increase, resulting in a 3% decrease in product purity. When the temperature drops to 78 °C, the reaction rate significantly slows down, and the precursor yield is only 60% after reacting for 2 hours.

[0014] A method for efficiently preparing high - purity rare earth metal oxides of the present invention: dissolving rare earth metal raw materials in ethanol to obtain a first solution; reacting an organic acid with the first solution to form a mixed complex salt; adding an oxygen aerosol to the mixed complex salt and reacting the mixed complex salt by combining UV light treatment to form a rare earth oxide precursor; performing pyrolysis treatment on the rare earth oxide precursor to obtain high - purity rare earth metal oxides. This method introduces organic acid H2C2O4 as a complex salt ligand to stabilize rare earth ions, achieving the uniformity and stability of the reaction. Using an oxygen aerosol and UV light treatment to increase the reaction rate and control the structure of the product, combining microscopic control techniques, optimizing reaction parameters and structure design, regulating the morphology and lattice structure of rare earth oxides, improving the preparation efficiency of rare earth metal oxides, and obtaining a higher purity. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of cerium oxide (CeO2) prepared by the present invention.

[0017] Figure 2It is a flow chart of a method for efficiently preparing high-purity rare earth metal oxides provided by the present invention. Detailed implementation manners

[0018] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0019] Please refer to Figures 1 to 2 , the present invention provides a method for efficiently preparing high-purity rare earth metal oxides, including the following steps:

[0020] S1 Dissolve rare earth metal raw materials in ethanol to obtain a first solution;

[0021] In the embodiment of the present invention, the rare earth metal raw material is RE2(C2O4)3, the purity should reach more than 99.9%, the concentration remains 1 mol / L, detected by inductively coupled plasma emission spectrometry, the total content of impurity elements is less than 0.1%, and the ethanol solvent is of analytical pure grade with a purity of at least 99.7%. It can be distilled and purified at 78-80 °C before use. To ensure the full dissolution of the rare earth metal raw materials, the dosage of the ethanol solvent can be appropriately adjusted so that the mass-volume ratio of the rare earth metal raw materials to the ethanol is between 1:10 and 1:15. Specifically, take a certain amount of cerium salt (such as Ce(NO3)3) powder and dissolve it in ethanol to prepare a Ce(NO3)3 solution with a concentration of 1 mol / L.

[0022] S2 React the first solution with an organic acid to generate a mixed complex salt;

[0023] In the embodiment of the present invention, the organic acid is H2C2O4 with a purity of not less than 99%. The proportion of the impurity peak area detected by high performance liquid chromatography is less than 1%. It is optimized within the range of 0.95-1.05:1 in terms of molar ratio. When the molar ratio is 1.02:1, the reaction yield can be increased by 5%.

[0024] The reaction formula is as follows:

[0025] RE2(C2O4)3 + 3H2C2O4 → RE2(C2O4)6 + 3H2O

[0026] Specifically, add an appropriate amount of organic acid (such as oxalic acid H2C2O4) to the Ce(NO3)3 solution to generate a mixed complex salt through a coordination reaction.

[0027] Oxygen aerosol is transported into the reactor while UV light treatment is carried out to accelerate the reaction rate. The mixed complex salt is exposed to an oxygen atmosphere to promote the oxidation reaction of cerium element, generating a precursor of cerium oxide.

[0028] S3 Add oxygen aerosol to the mixed complex salt and react the mixed complex salt by combining UV light treatment to form a rare earth oxide precursor;

[0029] In the embodiment of the present invention, the reaction formula is as follows:

[0030] RE2(C2O4)6 + O2 → RE2O3 + 6CO2 + H2O

[0031] The reaction temperature is optimized within the range of 78 - 82 °C. Experiments have found that when the temperature is 80 °C, the reaction rate is moderate and the yield is relatively high. At this temperature, after reacting for 1 hour, the yield of the rare earth oxide precursor can reach about 70%. When the temperature rises to 82 °C, the reaction rate increases, but the side reactions increase, resulting in a decrease in the product purity by about 3%; while when the temperature drops to 78 °C, the reaction rate significantly slows down, and the precursor yield is only 60% after reacting for 2 hours. Experiments are carried out within the pressure range of 1 - 1.2 atm. At a pressure of 1.1 atm, the reaction rate is increased by about 10% compared to normal pressure, and the yield can be correspondingly increased by about 8%. A high-pressure reaction kettle is used for the reaction, and the pressure fluctuation range is controlled within ±0.05 atm.

[0032] The concentration of the oxygen aerosol is optimized between 8% - 12% (mass - volume fraction). When the concentration is 10.5%, after testing, the yield of the rare earth oxide precursor is the highest, and the purity can also reach the best level. The flow rate of the oxygen aerosol can be controlled at 0.5 - 1 L / min to ensure its uniform dispersion in the reaction system.

[0033] The UV light intensity is optimized between 800 - 1200 lux, and the light exposure time is adjusted between 25 - 35 minutes. When the light intensity is 1000 lux and the light exposure time is 30 minutes, the comprehensive effects of the yield and purity of the precursor (CeO2) are better. At the same time, the distance between the UV lamp and the reaction vessel is maintained at 10 - 15 cm to ensure the uniformity of light exposure.

[0034] The purpose of adding oxygen aerosol

[0035] I. Oxidation: In the reaction system, oxygen is an important oxidant. After the rare earth metal raw material reacts with organic acid to form a salt ligand compound, the addition of oxygen aerosol can provide sufficient oxygen source for the subsequent reaction. In this process, oxygen participates in the oxidation reaction, promoting the change of oxidation state of some elements (such as rare earth elements) in the complex salt ligand compound and converting them into the oxidation state in the rare earth oxide precursor, which is one of the key steps in the formation of rare earth oxide precursor.

[0036] II. Improving reaction kinetics: The addition of oxygen aerosol can increase the collision probability between reactants in the reaction system. Oxygen in aerosol state can be more evenly dispersed in the reaction system and fully contact with the complex salt ligand compound, thus accelerating the reaction process and improving the reaction efficiency. This helps to generate more rare earth oxide precursors in a shorter time, which is of great significance for large-scale and efficient preparation processes.

[0037] III. Adjusting product structure: By controlling the concentration of oxygen aerosol, the structure of the generated rare earth oxide precursor can be affected. Appropriate oxygen content can make the structure of the precursor more regular, which is conducive to the formation of rare earth oxides with high purity and good uniformity during the subsequent pyrolysis process. For example, oxygen can combine with some active sites in the complex salt ligand compound to guide the growth direction and crystallization mode of the precursor, thus realizing the preliminary regulation of the product structure.

[0038] Purpose of combining with UV light treatment

[0039] I. Photocatalytic reaction: UV light irradiation may play a role in photocatalysis in the reaction. Many chemical reactions can be excited under the irradiation of ultraviolet light, reducing the activation energy of the reaction. In this system, UV light irradiation may excite the chemical bonds in the complex salt ligand compound, making it easier to react with oxygen. For example, UV light can cause some electrons in the complex salt ligand compound to transition to higher energy levels, forming active intermediates, which can react quickly with oxygen molecules in the oxygen aerosol, thus accelerating the generation of rare earth oxide precursors.

[0040] II. Improving reaction selectivity: Light irradiation treatment can improve the reaction selectivity. In a complex reaction system, there may be multiple reaction pathways. Through UV light irradiation, the reaction can be guided to proceed in the direction of generating rare earth oxide precursors. For example, light irradiation can selectively activate the chemical bonds related to rare earth elements, making these chemical bonds react with oxygen preferentially and inhibiting the occurrence of other side reactions, thus improving the yield and purity of rare earth oxide precursors.

[0041] III. Microstructure Regulation: UV light irradiation can finely regulate the microstructure of the generated rare earth oxide precursors. The energy of light can affect the crystallization process of the precursors, such as controlling the crystal growth direction, the formation rate of crystal nuclei, etc. Irradiation for 30 minutes with an intensity of 1000 lux can make the precursors form a more uniform structure at the microscale, which is of great significance for finally obtaining high-purity and well-controllable rare earth oxide products, because the microstructure of the precursors will directly affect the performance and quality of the rare earth oxides after pyrolysis.

[0042] Reaction Process Parameter Control and Optimization

[0043] I. Stirring Speed and Method:

[0044] For magnetic stirring, the stirring speed is optimized within the range of 300 - 500 rpm. When the stirring speed is 400 rpm, the reactants are mixed sufficiently, and the reaction yield can be increased by about 3%. If mechanical stirring is adopted, the rotational speed of the stirring blade is between 200 - 400 rpm, and the shape of the stirring blade can be selected as a three-blade inclined paddle type, which has better shearing and mixing effects on the reactants.

[0045] II. Reaction Time Control:

[0046] By monitoring the reaction progress in real time, such as observing the change of characteristic absorption peaks using ultraviolet-visible spectroscopy (UV-Vis). When the reaction proceeds for 1.5 - 2 hours, the characteristic absorption peaks of the reactants basically disappear, and the reaction reaches the end point at this time. Avoid the reaction time exceeding 2.5 hours to prevent side reactions from occurring and resulting in a decrease in product purity.

[0047] Product Processing Link Parameters

[0048] I. Precursor Purification:

[0049] After generating the rare earth oxide precursors, the filtration method is adopted, and the pore size of the filter paper is selected as 0.45 - 0.55 μm. During washing, first wash with deionized water 3 - 5 times, and the amount of washing liquid each time is 5 - 10 times the mass of the precursors. Then wash with absolute ethanol 2 - 3 times, and the amount of each time is 3 - 5 times the mass of the precursors, which can increase the purity of the precursors by about 7%. The washed precursors are vacuum dried at 60 - 80 °C for 6 - 8 hours, and the vacuum degree is maintained at -0.08 - 0.1 MPa to remove moisture and solvents.

[0050] S4 Perform pyrolysis treatment on the rare earth oxide precursors to obtain high-purity rare earth metal oxides.

[0051] In the embodiment of the present invention, the pyrolysis treatment temperature is optimized in the range of 880-920°C, and the holding time is adjusted between 1.8-2.2 hours. When the temperature is 900°C and the time is 2 hours, and the pyrolysis is carried out under the protection of an inert gas with an argon flow rate of 20-30 mL / min, the yield and purity of the rare earth oxide (CeO2) are the best.

[0052] Specifically, the obtained CeO2 precursor is placed in a heat treatment furnace and pyrolyzed at a high temperature (about 900°C) for 2 hours to remove residual organic matter from the precursor, and finally a high-purity, well-controllable cerium oxide (CeO2) product is obtained.

[0053] In order to better understand the present technical solution, the following embodiments are provided for further explanation:

[0054] Raw material purity control comparison

[0055] Initial state:

[0056] When the purity of raw materials is not strictly controlled, the rare earth metal raw material RE2(C2O4)3 may contain more impurities. Assuming the impurity content is 1-2% (detected by ICP-AES), these impurities may include other rare earth element impurities, a small amount of heavy metal elements (such as iron, copper, etc.) and incompletely reacted production intermediates. The purity of organic acid H2C2O4 is assumed to be about 98% (the impurity peak area accounts for about 2% by HPLC detection), and the purity of ethanol solvent is 99.7%, but it may contain trace amounts of water and other organic impurities.

[0057] After optimization:

[0058] After optimization, the purity of the rare earth metal raw material RE2(C2O4)3 reaches more than 99.9%, and the total content of impurity elements is less than 0.1%. The purity of the organic acid H2C2O4 is not less than 99%, and the impurity peak area accounts for less than 1%. After distillation and purification of the ethanol solvent, the purity can be further improved and the impurity content is significantly reduced. This increase in raw material purity directly reduces the possibility of impurities entering the reaction system, laying the foundation for the subsequent improvement of the purity of rare earth oxides. For example, in the subsequent reaction and product processing process, high-purity raw materials can reduce side reactions caused by impurities, so that the purity of the final rare earth oxide is better guaranteed at the initial stage.

[0059] Optimization comparison of raw material ratio

[0060] Initial state:

[0061] When the rare earth metal raw material RE2(C2O4)3 and the organic acid H2C2O4 react in a molar ratio of 1:1, due to the incomplete reaction between the raw materials, some of the rare earth metal raw materials may not fully participate in the reaction, and the purity of the rare earth oxide precursor formed is affected to a certain extent. For example, there may be residues of unreacted rare earth metal raw materials, thus reducing the product purity.

[0062] After optimization:

[0063] After adjusting the molar ratio of the organic acid H2C2O4 to 1.02:1, experiments found that the reaction of the rare earth metal raw materials was more complete. Through chemical analysis, after the reaction ended, the residual amount of unreacted rare earth metal raw materials decreased by about 30% compared to the initial state, which increased the purity of the rare earth oxide precursor by about 3 - 5%. At the same time, optimizing the mass-volume ratio of the raw materials and ethanol ensured the full dissolution of the raw materials, further improving the completeness of the reaction, which had a positive effect on the improvement of the final rare earth oxide purity.

[0064] Comparison of optimized reaction conditions

[0065] Comparison of temperature control

[0066] Initial state: When the reaction temperature is 80°C, the reaction rate is moderate. However, if the temperature control is not precise enough and the fluctuation range is large (for example, ±3 - 5°C), side reactions may occur. For example, too high a temperature may cause some reactants to decompose, or trigger other unwanted redox reactions, thus reducing the purity of the rare earth oxide. Assume that in this case, the product purity is about 95%.

[0067] After optimization: The temperature is controlled within the range of 78 - 82°C, and the fluctuation range is reduced to ±2°C. By precisely controlling the temperature, side reactions caused by temperature fluctuations are reduced. Under the optimized temperature conditions, the product purity can be increased to 97 - 98%, and the yield can also be maintained at a relatively high level.

[0068] Comparison of pressure adjustment

[0069] Initial state: Reacting under normal pressure, the collision probability between reactant molecules is relatively low, and the reaction rate is limited to a certain extent. In this case, the reaction may take a long time to reach a high yield, and due to the insufficient reaction, the product purity will also be affected.

[0070] After optimization: When the pressure is adjusted to 1.1 atm, the reactant concentration increases relatively, and the reaction rate is about 10% higher than that under normal pressure. The reaction is more complete, which increases the purity of the rare earth oxide by about 3 - 5% and the yield by about 8% accordingly.

[0071] Comparison of optimization of oxygen aerosol and UV light

[0072] Oxygen aerosol

[0073] Initial state: When the concentration of oxygen aerosol is 10% and conditions such as flow rate are not optimized, uneven distribution of oxygen may occur, resulting in incomplete oxidation of some reactants. This may cause the purity of the rare earth oxide precursor to be around 94%.

[0074] After optimization: Adjust the concentration of oxygen aerosol to 10.5% and control the flow rate at 0.5 - 1 L / min to ensure uniform dispersion of oxygen in the reaction system. Through testing, it is found that the purity of the rare earth oxide precursor can be increased to 96 - 97%, and the yield also increases.

[0075] UV light irradiation

[0076] Initial state: When the UV light intensity is 1000 lux and the irradiation time is 30 minutes, but the uniformity of light irradiation is not optimized (such as the inappropriate distance between the lamp and the reaction vessel), local light intensity may be too strong or too weak, affecting the selectivity of the reaction. The product purity may be around 95%.

[0077] After optimization: Keep the distance between the UV lamp and the reaction vessel at 10 - 15 cm to ensure the uniformity of light irradiation. At the same time, optimize within the range of light intensity 800 - 1200 lux and irradiation time 25 - 35 minutes. It is found that when the light intensity is 1000 lux and the irradiation time is 30 minutes, the comprehensive effect of the precursor yield and purity is better, and the purity can be increased to 97 - 98%.

[0078] Comparison of reaction process optimization

[0079] Comparison of stirring speed and method

[0080] Initial state: If the stirring speed is inappropriate, such as the magnetic stirring speed is 200 rpm or the rotational speed of the mechanical stirring impeller is 100 rpm, the reactants are not mixed sufficiently. This may lead to too high or too low local reactant concentration, uneven reaction, and the purity of the rare earth oxide precursor may be between 94 - 95%.

[0081] After optimization: For magnetic stirring, adjust the speed to 400 rpm, or use a three - blade inclined - paddle mechanical stirring impeller with a rotational speed between 200 - 400 rpm to mix the reactants sufficiently. This optimized stirring method can make the reaction more uniform, and the purity of the rare earth oxide precursor can be increased to 96 - 97%.

[0082] Comparison of reaction time control

[0083] Initial state: If the reaction time is not accurately controlled, when the reaction time is too long (exceeding 2.5 hours), side reactions may be triggered, such as excessive oxidation or decomposition of the precursor, resulting in a decrease in the purity of the product. Assuming that in the initial state, due to improper control of the reaction time, the product purity is between 93 - 94%.

[0084] After optimization: By real-time monitoring of the reaction progress (such as observing characteristic absorption peaks by UV-Vis), the reaction time is controlled between 1.5 - 2 hours, avoiding the occurrence of side reactions. This can increase the product purity to 96 - 97%.

[0085] Optimization comparison of the product treatment process

[0086] Purification comparison of the precursor

[0087] Initial state: If after generating the rare earth oxide precursor, only simple filtration and washing are carried out, for example, only washed with deionized water 1 - 2 times, and the filter paper pore size is relatively large (0.8 - 1μm), impurities may not be effectively removed. At this time, the precursor purity may be about 95%.

[0088] After optimization: More refined filtration (filter paper pore size 0.45 - 0.55μm) is adopted, and washed with deionized water 3 - 5 times, with the amount of washing liquid each time being 5 - 10 times the mass of the precursor, and then washed with anhydrous ethanol 2 - 3 times, with the amount each time being 3 - 5 times the mass of the precursor. Through these optimization measures, the precursor purity can be increased to 97 - 98%.

[0089] Optimization comparison of the pyrolysis process

[0090] Initial state: During the pyrolysis process, if the pyrolysis temperature is not accurately controlled (for example, the temperature fluctuates by ±20 - 30°C), or it is not carried out under the protection of an inert gas, it may cause the rare earth oxide to react with oxygen or other impurities in the air. Assuming that in the initial state, due to poor control of the pyrolysis process, the purity of the rare earth oxide is 94 - 95%.

[0091] After optimization: The pyrolysis treatment temperature is controlled within the range of 880 - 920°C, the fluctuation range is reduced to ±10 - 15°C, the holding time is adjusted between 1.8 - 2.2 hours, and the pyrolysis is carried out under the protection of an inert gas with an argon flow rate of 20 - 30 mL / min. Through these optimizations, the purity of the rare earth oxide can be increased to 97 - 98%.

[0092] What is disclosed above is only a preferred embodiment of an efficient preparation method of high-purity rare earth metal oxides of the present invention. Of course, the scope of rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A method for efficiently preparing high-purity rare earth metal oxides, characterized in that: The following steps are involved: Dissolving a rare earth metal raw material in ethanol to obtain a first solution; Using an organic acid to react with the first solution to generate a mixed complex salt; Adding oxygen aerosol to the mixed complex salt, and reacting the mixed complex salt in combination with UV light treatment to form a rare earth oxide precursor; The rare earth oxide precursor is subjected to pyrolysis treatment to obtain high-purity rare earth metal oxide.

2. The method for efficiently preparing high-purity rare earth metal oxide according to claim 1, characterized in that ； The rare earth metal raw material is RE2(C2O4)3, the purity should reach above 99.9%, the concentration should still be maintained at 1 mol / L, and the total content of impurity elements is less than 0.1% by inductively coupled plasma emission spectroscopy detection.

3. The method for efficiently preparing high-purity rare earth metal oxide according to claim 1, characterized in that ； The ethanol solvent is of analytical grade with a purity of at least 99.7%. It can be distilled and purified at 78-80° C. before use. To ensure that the rare earth metal raw material is fully dissolved, the amount of the ethanol solvent can be appropriately adjusted so that the mass volume ratio of the rare earth metal raw material to the ethanol is between 1:10 and 1:

15.

4. The method for efficiently preparing high-purity rare earth metal oxide according to claim 1, characterized in that ； The organic acid is H2C2O4 with a purity of not less than 99%, and the impurity peak area detected by high performance liquid chromatography accounts for less than 1%. The molar ratio is optimized within the range of 0.95-1.05:

1. When the molar ratio is 1.02:1, the reaction yield can be increased by 5%.

5. The method for efficiently preparing high-purity rare earth metal oxide according to claim 1, It is characterized by: The reaction temperature of the UV light treatment is optimized in the range of 78-82°C. When the temperature is 80°C, the reaction rate is moderate and the yield is high. At this temperature, after 1 hour of reaction, the yield of the rare earth oxide precursor can reach 70%. When the temperature is increased to 82°C, the reaction rate is accelerated, but the side reactions increase, resulting in a 3% decrease in product purity. When the temperature is reduced to 78°C, the reaction rate is significantly slowed down, and the precursor yield is only 60% after 2 hours of reaction.

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