Preparation method of europium fluoride for fluorescent material
Through a new preparation method, the reaction of europium hydroxide and mixed acid solution was used, combined with rinsing and spray-drying steps, the problem of large particle size and low purity of europium fluoride was solved, and a small-particle size fluoride powder with high purity and uniform particle size was prepared, which improved the quality stability of fluorescent materials.
Patent Information
- Application Number
- CN202411852647.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-14
AI Technical Summary
The europium fluoride prepared in the prior art has a large particle size and low purity, and cannot be directly used in fluorescent materials. It is necessary to introduce mechanical impurities during further pulverization, resulting in unstable mass.
A preparation method is adopted, which includes mixing europium hydroxide with water and ethoxymethylpropanol, adding a mixed acid solution of hydrofluoric acid and hydrochloric acid to react, and after rinsing and pH adjustment, obtaining europium fluoride powder by spray drying.
A small-particle size europium fluoride powder with uniform particle size and high purity is achieved, avoiding the mechanical impurities introduced by further grinding and improving the quality stability of the product.
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Figure CN119612577A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of fluorescent materials, and in particular to a method for preparing europium fluoride for fluorescent materials. Background Art
[0002] Europium fluoride is a rare earth fluoride, which is mainly used in fluorescent materials, special optical glass, optoelectronic ceramics, laser crystals, metal smelting and other fields. There are two main requirements for the application of europium fluoride in the field of fluorescent materials: first, it must have a finer particle size and the particle size must be very uniform; second, it must have a higher purity and the impurity ions must be controlled in a lower range. Europium fluoride used in the field of fluorescence is a new material. The europium fluoride prepared in the existing technology has a larger particle size and lower purity and cannot be directly used in fluorescent materials. It needs to be air flow crushed or ball milled before being used as a fluorescent material. In addition, more mechanical impurities will be introduced during the crushing process, resulting in unstable quality of europium fluoride powder.
[0003] Therefore, it is necessary to provide a method for preparing europium fluoride for fluorescent materials, which can mass-produce europium fluoride that can be directly used in fluorescent materials. Summary of the invention
[0004] The invention provides a method for preparing europium fluoride for fluorescent materials, which solves the problem in the related art that europium fluoride has large particle size and low purity and is difficult to be directly used as a fluorescent material.
[0005] The technical solution of the present invention is as follows: The present invention provides a method for preparing europium fluoride for fluorescent material, comprising the following steps: S1, mixing europium hydroxide and water, adding the first ethoxymethyl propane alcohol and continuing to mix, to obtain europium hydroxide slurry; S2, mixing the hydrofluoric acid solution and hydrochloric acid to obtain a mixed acid solution; S3, heating the mixed acid solution to 50-80° C., adding the europium hydroxide slurry to react, and obtaining a europium fluoride synthesis solution; S4, rinsing the europium fluoride synthesis solution, adding a pH adjuster and a second ethoxymethyl propane alcohol in sequence to obtain a europium fluoride spray solution, and spray drying to obtain a europium fluoride powder.
[0006] As a further technical solution, the mass ratio of water to europium hydroxide is 1:2~4.
[0007] As a further technical solution, the pH regulator adjusts the pH of the europium fluoride synthesis solution to 5-8.
[0008] As a further technical solution, the mass of the first ethoxymethylpropane alcohol is 1% to 3% of the mass of the europium hydroxide.
[0009] As a further technical solution, the hydrofluoric acid solution is an electronic grade hydrofluoric acid aqueous solution with a volume fraction of 25%; The mass of the hydrochloric acid is 5% to 15% of the mass of the hydrofluoric acid solution.
[0010] As a further technical solution, the molar ratio of hydrofluoric acid to the europium hydroxide is 3.5-4:1.
[0011] As a further technical solution, the rotation speed during the reaction is 50-100 r / min, the temperature is above 80° C., and the time is 2-5 h.
[0012] As a further technical solution, during the rinsing, the free acid content of the europium fluoride synthesis solution is rinsed to less than 0.2%; The pH regulator is aqueous ammonia; The mass of the second ethoxymethyl propane alcohol is 0.5% to 2% of the mass of the europium fluoride synthesis solution; As a further technical solution, the air inlet temperature during spray drying is 600-800°C, the air outlet temperature is 400-600°C, and the liquid inlet speed is 1-3 kg / min.
[0013] In the present invention, the air inlet temperature is 600-800°C and the air outlet temperature is 400-600°C during spray drying, in order to remove the water or oxygen in europium fluoride relatively cleanly and to volatilize ethoxymethyl propanol (EGMP) cleanly.
[0014] As a further technical solution, the particle size D0.5 of the europium fluoride powder is 0.8-1.2 μm, and D0.97 is 3-8 μm.
[0015] In the present invention, compared with the existing process for producing europium fluoride, the particle size of europium trifluoride is directly synthesized into small particles of 0.5-8 μm from the source, thereby avoiding the risk of unstable quality caused by the introduction of more mechanical impurities due to further grinding, and preventing excessive adhesion during the drying process by adding ethoxymethyl propane alcohol, and preventing excessive corrosion of equipment by adjusting the pH value to around neutral, thereby preparing a europium fluoride material with uniform particle size and small particle size.
[0016] In the present invention, the reaction equation for preparing europium fluoride is: Eu(OH)3+3HF=EuF3+3H2O.
[0017] The present invention also proposes the use of the europium fluoride powder prepared by the method for preparing europium fluoride for fluorescent materials in fluorescent materials.
[0018] The working principle and beneficial effects of the present invention are: In the present invention, ethoxymethyl propane alcohol (EGMP) is added twice when preparing europium fluoride to prevent the formation of large europium fluoride particles and keep the europium fluoride particles relatively uniform during synthesis. The second addition of EGMP can also prevent the particles from becoming larger due to the adhesion of ions during the spraying process. At the same time, hydrochloric acid is added to the mixed acid solution to increase the acidity of hydrofluoric acid and catalyze the generation of europium fluoride. The preparation method of the present invention is finally used to prepare high-purity europium fluoride with a particle size D0.5 of 0.8-1.2 μm and a D0.97 of 3-8 μm. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0020] Figure 1 The XRD spectrum of the europium fluoride powder prepared in Example 1 of the present invention; Figure 2 This is a particle size distribution diagram of the europium fluoride powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.
[0022] In the following embodiments, the hydrofluoric acid solution is an electronic grade hydrofluoric acid aqueous solution with a volume fraction of 25%; the hydrochloric acid is analytical grade; and the purity of the electronic grade hydrofluoric acid is ≥99.99%.
[0023] Example 1 The preparation method of europium fluoride for fluorescent material comprises the following steps: S1. Slurry and disperse europium hydroxide and high-purity water in a mass ratio of 3:1, add ethoxymethylpropanol and continue mixing to obtain europium hydroxide slurry; wherein the mass of ethoxymethylpropanol is 1% of the mass of europium hydroxide; S2, mixing the hydrofluoric acid solution and hydrochloric acid evenly to obtain a mixed acid solution; wherein the mass of the hydrochloric acid is 10% of the mass of the hydrofluoric acid solution; S3. After the mixed acid solution is heated to 70°C, europium hydroxide slurry is added under stirring conditions (rotation speed is 80r / min), the speed of adding europium hydroxide slurry is 5kg / min, and after the addition, the mixture is reacted at above 80°C for 4h to obtain europium fluoride synthesis liquid (during the reaction, the oxygen content in the synthesis liquid is taken to control whether the europium fluoride is completely reacted, and the reaction is considered to be complete if the oxygen content is less than 0.15%); the molar ratio of hydrofluoric acid to europium hydroxide is 3.5:1; S4. Put the europium fluoride synthesis liquid into a sedimentation barrel, add ultrapure water for rinsing, rinse until the free acid content is less than 0.2%, add ammonia water to adjust the pH to 5-8, and stir for 30 minutes to ensure that the pH value is stable at 5-8, then add ethoxymethyl propane alcohol for mixing to obtain europium fluoride spray liquid, and spray dry it with a ceramic-lined spray dryer to obtain europium fluoride powder (qualitatively europium trifluoride, particle size D0.5 is 0.8-1.2μm, D0.97 is 3-8μm; detected by nitrogen and oxygen meter: the oxygen content in europium trifluoride is less than 0.2%; detected by ICP-OES-5110: the content of transition metal impurities such as cobalt, nickel, copper, titanium, vanadium, cadmium, chromium, etc. is less than 1ppm, and the iron content is 1.3ppm), the XRD spectrum of the europium fluoride powder is as follows Figure 1 As shown, the particle size distribution of europium fluoride powder is as follows Figure 2 As shown; wherein, the mass of ethoxymethylpropane alcohol is 1% of the mass of europium fluoride synthesis liquid, the inlet air temperature during spray drying is 600°C, the outlet air temperature is 400°C, and the liquid inlet speed is 1kg / min.
[0024] Example 2 The preparation method of europium fluoride for fluorescent material comprises the following steps: S1. Slurry and disperse europium hydroxide and high-purity water in a mass ratio of 3:1, add ethoxymethylpropane alcohol and continue mixing to obtain europium hydroxide slurry; wherein the mass of ethoxymethylpropane alcohol is 1.5% of the mass of europium hydroxide; S2. Evenly mix the hydrofluoric acid solution and hydrochloric acid to obtain a mixed acid solution; wherein the mass of the hydrochloric acid is 8% of the mass of the hydrofluoric acid solution; S3. After the mixed acid solution is heated to 75°C, europium hydroxide slurry is added under stirring conditions (rotation speed is 70r / min), the speed of adding europium hydroxide slurry is 5kg / min, and after the addition, the mixture is reacted at above 80°C for 3.5h to obtain europium fluoride synthesis liquid (during the reaction, the oxygen content in the synthesis liquid is taken to control whether the europium fluoride is completely reacted, and the reaction is considered to be complete when the oxygen content is less than 0.15%); the molar ratio of hydrofluoric acid to europium hydroxide is 4:1; S4. Put the europium fluoride synthetic liquid into a sedimentation barrel, add ultrapure water for rinsing, rinse until the free acid content is less than 0.2%, add ammonia water to adjust the pH to 5-8, and stir for 30 minutes to ensure that the pH value is stable at 5-8, then add ethoxymethyl propane alcohol for mixing to obtain europium fluoride spray liquid, and spray dry it with a ceramic-lined spray dryer to obtain europium fluoride powder (qualitatively europium trifluoride, particle size D0.5 is 0.8-1.2μm, D0.97 is 3~8μm; detected by nitrogen oxygen meter: the oxygen content in europium trifluoride is less than 0.2%; detected by ICP-OES-5110: the content of transition metal impurities such as cobalt, nickel, copper, titanium, vanadium, cadmium, chromium, etc. is less than 1ppm, and the iron content is 1.8ppm); among them, the mass of ethoxymethylpropane alcohol is 1% of the mass of europium fluoride synthesis liquid, the inlet temperature during spray drying is 700℃, the outlet temperature is 500℃, and the liquid inlet speed is 2kg / min.
[0025] Example 3 The preparation method of europium fluoride for fluorescent material comprises the following steps: S1. Slurry and disperse europium hydroxide and high-purity water in a mass ratio of 3:1, add ethoxymethylpropane alcohol and continue mixing to obtain europium hydroxide slurry; wherein the mass of ethoxymethylpropane alcohol is 2% of the mass of europium hydroxide; S2, mixing the hydrofluoric acid solution and hydrochloric acid evenly to obtain a mixed acid solution; wherein the mass of the hydrochloric acid is 15% of the mass of the hydrofluoric acid solution; S3. After the mixed acid solution is heated to 80°C, europium hydroxide slurry is added under stirring conditions (rotation speed is 65r / min), the speed of adding europium hydroxide slurry is 5kg / min, and after the addition, the mixture is reacted at above 80°C for 4.5h to obtain europium fluoride synthesis liquid (during the reaction, the oxygen content in the synthesis liquid is taken to control whether the europium fluoride is completely reacted, and the reaction is considered to be complete if the oxygen content is lower than 0.15%); the molar ratio of hydrofluoric acid to europium hydroxide is 3.8:1; S4, put the europium fluoride synthetic liquid into a sedimentation barrel, add ultrapure water for rinsing, rinse until the free acid content is less than 0.2%, add ammonia water to adjust the pH to 5-8, and stir for 30 minutes to ensure that the pH value is stable at 5-8, then add ethoxymethyl propane alcohol for mixing to obtain europium fluoride spray liquid, and spray dry it with a ceramic-lined spray dryer to obtain europium fluoride powder (after testing, it is qualitatively identified as europium trifluoride, with a particle size D0.5 of 0.8-1.2 μm, D0. 97 is 3~8μm; detected by nitrogen oxygen meter: the oxygen content in europium trifluoride is less than 0.2%; detected by ICP-OES-5110: the content of transition metal impurities such as cobalt, nickel, copper, titanium, vanadium, cadmium, chromium, etc. is less than 1ppm, and the iron content is 1.6ppm); among them, the mass of ethoxymethylpropane alcohol is 1% of the mass of europium fluoride synthesis liquid, the inlet temperature during spray drying is 750℃, the outlet temperature is 530℃, and the liquid inlet speed is 3kg / min.
[0026] Comparative Example 1 The preparation method of europium fluoride for fluorescent material comprises the following steps: S1. Slurry and disperse europium hydroxide and high-purity water in a mass ratio of 3:1, add ethoxymethylpropane alcohol and continue mixing to obtain europium hydroxide slurry; wherein the mass of ethoxymethylpropane alcohol is 2% of the mass of europium hydroxide; S2, mixing the hydrofluoric acid solution and hydrochloric acid evenly to obtain a mixed acid solution; wherein the mass of the hydrochloric acid is 15% of the mass of the hydrofluoric acid solution; S3. After the mixed acid solution is heated to 80°C, europium hydroxide slurry is added under stirring conditions (rotation speed is 65r / min), the speed of adding europium hydroxide slurry is 5kg / min, and after the addition, the mixture is reacted at above 80°C for 4.5h to obtain europium fluoride synthesis liquid (during the reaction, the oxygen content in the synthesis liquid is taken to control whether the europium fluoride is completely reacted, and the reaction is considered to be complete if the oxygen content is lower than 0.15%); the molar ratio of hydrofluoric acid to europium hydroxide is 3.8:1; S4. Put the europium fluoride synthesis liquid into a sedimentation barrel, add ultrapure water for rinsing, rinse until the free acid content is less than 0.2%, add ammonia water to adjust the pH to 5-8, and stir for 30 minutes to ensure that the pH value is stable at 5-8, then obtain the europium fluoride spray liquid, and spray dry it with a ceramic-lined spray dryer to obtain europium fluoride powder (qualitatively characterized as europium trifluoride, with a particle size D0.5 of 3-4μm and D0.97 of 9-13μm; detected by a nitrogen oxygen meter: the oxygen content in europium trifluoride is less than 0.2%; detected by ICP-OES-5110: the content of transition metal impurities such as cobalt, nickel, copper, titanium, vanadium, cadmium, and chromium is less than 1ppm, and the iron content is 1.6ppm); wherein, the mass of ethoxymethylpropane alcohol is 1% of the mass of the europium fluoride synthesis liquid, the inlet temperature during spray drying is 750℃, the outlet temperature is 530℃, and the liquid inlet speed is 3kg / min.
[0027] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing europium fluoride for fluorescent material, characterized in that: The following steps are involved: S1, mixing europium hydroxide and water, adding the first ethoxymethyl propane alcohol and continuing to mix, to obtain europium hydroxide slurry; S2, mixing the hydrofluoric acid solution and hydrochloric acid to obtain a mixed acid solution; S3, heating the mixed acid solution to 50-80° C., adding the europium hydroxide slurry to react, and obtaining a europium fluoride synthesis solution; S4, rinsing the europium fluoride synthesis solution, adding a pH adjuster and a second ethoxymethyl propane alcohol in sequence to obtain a europium fluoride spray solution, and spray drying to obtain a europium fluoride powder.
2. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The mass ratio of water to europium hydroxide is 1:2-4.
3. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The mass of the first ethoxymethylpropane alcohol is 1% to 3% of the mass of the europium hydroxide.
4. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The hydrofluoric acid solution is an electronic grade hydrofluoric acid aqueous solution with a volume fraction of 25%; The mass of the hydrochloric acid is 5% to 15% of the mass of the hydrofluoric acid solution.
5. The method for preparing europium fluoride for fluorescent material according to claim 4, characterized in that: The molar ratio of hydrofluoric acid to the europium hydroxide is 3.5-4:
1.
6. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The reaction speed is 50-100 r / min, the temperature is above 80° C., and the reaction time is 2-5 hours.
7. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The mass of the second ethoxymethyl propane alcohol is 0.5% to 2% of the mass of the europium fluoride synthesis solution.
8. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: During the spray drying, the air inlet temperature is 600-800°C, the air outlet temperature is 400-600°C, and the liquid inlet speed is 1-3 kg / min.
9. The method for preparing europium fluoride for fluorescent material according to claim 1, characterized in that: The particle size D0.5 of the europium fluoride powder is 0.8-1.2 μm, and D0.97 is 3-8 μm.
10. Use of the europium fluoride powder obtained by the method for preparing europium fluoride for fluorescent materials according to any one of claims 1 to 9 in fluorescent materials.