Preparation method of lanthanum sesquioxide / praseodymium sesquioxide microspheres

Abstract

The present invention discloses a preparation method of lanthanum sesquioxide / praseodymium sesquioxide microspheres, which comprises the following steps: stirring and mixing glycerol and isopropanol evenly to obtain a first mixed solution; adding La(NO3)3·6H2O / Pr(NO3)3·6H2O to the obtained first mixed solution and stirring to make La(NO3)3·6H2O / Pr(NO3)3·6H2O evenly dispersed in the first mixed solution to prepare a second mixed solution; after the heating reaction of the second mixed solution is completed, cooling to room temperature to obtain a white precipitate; washing, centrifuging and drying the white precipitate to obtain the product La-glycerate / Pr-glycerate; calcining the La-glycerate / Pr-glycerate to prepare La2O3 microspheres / Pr2O3 microspheres. The method of the present invention has simple process, is easy to control, has high processing efficiency and low cost; the obtained product has regular morphology, uniform size and good dispersibility.

Description

Technical Field

[0001] The present invention relates to the field of production of rare earth oxides, and particularly to a method for preparing lanthanum sesquioxide / praseodymium sesquioxide microspheres. Background Art

[0002] In many cutting-edge fields such as materials science and chemical engineering, lanthanum sesquioxide (La2O3) and praseodymium sesquioxide (Pr2O3) occupy a pivotal position by virtue of their unique physical and chemical properties, becoming focus substances in the fields of scientific research and industrial applications.

[0003] Lanthanum sesquioxide, as an important rare earth metal oxide, appears as a white powdery substance. It is insoluble in water and ketones, but soluble in ethanol, ammonium chloride, and inorganic acids. When exposed to air, it can absorb carbon dioxide and water to form lanthanum carbonate. Lanthanum sesquioxide has a very wide range of uses and is applied in the fields of optical glass, ceramic capacitors, piezoelectric ceramics, and high-temperature superconducting materials.

[0004] Praseodymium sesquioxide is a yellowish-green or blackish-brown amorphous powder or block, with hygroscopic properties, easily absorbs carbon dioxide in the air, is soluble in acids, and insoluble in water. It is widely used in the fields of petrochemical industry, ceramic materials, and glass manufacturing.

[0005] With the rapid development of technology, the performance requirements for lanthanum sesquioxide and praseodymium sesquioxide in various fields are becoming increasingly stringent. Not only higher purity is required, but also precise control of their microstructures and morphologies is demanded. However, current conventional preparation methods often fall short when meeting these strict requirements and expose many problems.

[0006] Currently, the main methods for synthesizing spherical lanthanum sesquioxide / praseodymium sesquioxide (La2O3 / Pr2O3) are coprecipitation method, spray drying method, and hard template method. However, these methods face technical problems such as uneven and difficult-to-control product sizes, complex processes, and the removal of templates often requires the use of strong acids and strong bases, resulting in cumbersome processes and harsh conditions. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preparing lanthanum sesquioxide / praseodymium sesquioxide microspheres with simple process, easy control, uniform product size, and good dispersibility.

[0008] The present invention is implemented by the following technical solutions: A method for preparing lanthanum sesquioxide / praseodymium sesquioxide microspheres, which comprises the following steps:

[0009] (1) Prepare the first mixed solution: Stir and mix glycerol and isopropyl alcohol evenly to obtain the first mixed solution;

[0010] (2) Preparation of the second mixed solution: Add La(NO3)3·6H2O / Pr(NO3)3·6H2O to the prepared first mixed solution and stir to evenly disperse La(NO3)3·6H2O / Pr(NO3)3·6H2O in the first mixed solution, thereby preparing the second mixed solution;

[0011] (3) Heating reaction of the second mixed solution to prepare a white precipitate: After the heating reaction of the second mixed solution is completed, cool it to room temperature to obtain a white precipitate;

[0012] (4) Preparation of the product La-glycerate / Pr-glycerate: Wash, centrifuge, and dry the white precipitate to obtain the product La-glycerate / Pr-glycerate;

[0013] (5) Preparation of La2O3 microspheres / Pr2O3 microspheres: Calcinate the La-glycerate / Pr-glycerate to prepare La2O3 microspheres / Pr2O3 microspheres.

[0014] Further, in the step (1), the volume ratio of glycerol to isopropanol is 1:7.

[0015] Further, the concentration of La(NO3)3·6H2O / Pr(NO3)3·6H2O in the second mixed solution is 4 g / L - 5 g / L.

[0016] Further, in the step (3), the heating reaction temperature of the second mixed solution is 220 °C and the reaction time is 8 h.

[0017] Further, in the step (4), the drying temperature is 70 °C.

[0018] Further, in the step (5), the calcination heating rate is 2 °C / min -1 , heat up to 900 °C and calcine in air for 5 h.

[0019] Advantages of the present invention:

[0020] The method of the present invention has simple process, easy to control, high processing efficiency and low cost; the obtained product has regular morphology, uniform size and good dispersibility. Description of the Drawings

[0021] In order 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 the description of the embodiments or the prior art. Obviously, the drawings in the following description 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.

[0022] Figure 1 SEM image of La-gly prepared in Example 1;

[0023] Figure 2 SEM image of La2O3 microspheres prepared in Example 1;

[0024] Figure 3 SEM image of Pr-gly prepared in Example 2;

[0025] Figure 4 SEM image of Pr2O3 microspheres prepared in Example 2;

[0026] Figure 5 SEM image of La-gly prepared in Comparative Example 1;

[0027] Figure 6 SEM image of La2O3 microspheres prepared in Comparative Example 1;

[0028] Figure 7 SEM image of Pr-gly prepared in Comparative Example 2;

[0029] Figure 8 SEM image of Pr2O3 microspheres prepared in Comparative Example 2;

[0030] Figure 9 SEM image of La-gly prepared in Comparative Example 3;

[0031] Figure 10 SEM image of La2O3 microspheres prepared in Comparative Example 3;

[0032] Figure 11 SEM image of La-gly prepared in Comparative Example 4;

[0033] Figure 12 SEM image of La2O3 microspheres prepared in Comparative Example 4;

[0034] Figure 13 SEM image of Pr-gly prepared in Comparative Example 5;

[0035] Figure 14 SEM image of Pr2O3 microspheres prepared in Comparative Example 5;

[0036] Figure 15 SEM image of Pr-gly prepared in Comparative Example 6;

[0037] Figure 16 SEM image of Pr2O3 microspheres prepared in Comparative Example 6;

[0038] Figure 17SEM image of La-gly prepared in Comparative Example 7;

[0039] Figure 18 SEM image of La2O3 microspheres prepared in Comparative Example 7;

[0040] Figure 19 SEM image of La-gly prepared in Comparative Example 8;

[0041] Figure 20 SEM image of La2O3 microspheres prepared in Comparative Example 8;

[0042] Figure 21 SEM image of Pr-gly prepared in Comparative Example 9;

[0043] Figure 22 SEM image of Pr2O3 microspheres prepared in Comparative Example 9;

[0044] Figure 23 SEM image of Pr-gly prepared in Comparative Example 10;

[0045] Figure 24 SEM image of Pr2O3 microspheres prepared in Comparative Example 10. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Example 1: A preparation method of lanthanum sesquioxide microspheres specifically includes the following preparation steps:

[0048] (1) Preparation of lanthanum-based glycerate spheres

[0049] 8 mL of glycerol and 56 mL of isopropyl alcohol (IPA) were stirred for half an hour to be fully mixed evenly. 0.625 mmol of La(NO3)3·6H2O was stirred for 2 h to make La(NO3)3·6H2O evenly dispersed in the mixed solution. The mixed solution was poured into a 100 mL reaction kettle and reacted at 220 °C in a forced-air drying oven for 8 h. After the reaction kettle cooled to room temperature, the white precipitate was taken out, washed 3 times with absolute ethanol, and the centrifuged product was placed in a vacuum drying oven at 70 °C for drying. Finally, the product La-glycerate (La-gly) (lanthanum glycerate) was obtained, as Figure 1 shown, Figure 1 which is a SEM image with a magnification of 2000 times, Figure 1It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution ranges from 1.1 to 2.0 μm.

[0050] (2)Preparation of lanthanum sesquioxide microspheres

[0051] Place the La-gly / Pr-gly obtained in step (1) in a muffle furnace and calcine it in air at 900 °C for 5 h at a heating rate of 2 °C min -1 . After natural cooling to room temperature, La2O3 microspheres (La2O3-SSs) can be obtained respectively, as Figure 2 shown, Figure 2 which is a scanning electron microscope image at a magnification of 22000 times. Figure 2 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution ranges from 1.43 to 1.55 μm.

[0052] Example 2: Preparation method of praseodymium sesquioxide microspheres, specifically including the following preparation steps:

[0053] (1)Preparation of praseodymium-based glycerate spheres

[0054] Stir 8 mL of glycerol and 56 mL of isopropanol (IPA) for half an hour to mix them evenly. Stir 0.625 mmol of Pr(NO3)3·6H2O for 2 h to uniformly disperse Pr(NO3)3·6H2O in the mixed solution. Pour the mixed solution into a 100 mL reaction kettle and place it in a forced-air drying oven at 220 °C for 8 h. After the reaction kettle cools to room temperature, take out the white precipitate, wash it 3 times with absolute ethanol, centrifuge the obtained product, and dry it in a vacuum drying oven at 70 °C to finally obtain the product Pr-glycerate (Pr-gly) (praseodymium glycerate), as Figure 3 shown, Figure 3 which is a scanning electron microscope image at a magnification of 10000 times. Figure 3 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution ranges from 1.63 to 1.99 μm.

[0055] (2)Preparation of praseodymium sesquioxide microspheres

[0056] Place the Pr-gly obtained in step (1) in a muffle furnace and calcine it in air at 900 °C for 5 h at a heating rate of 2 °C min -1 . After natural cooling to room temperature, Pr2O3 microspheres (Pr2O3-SSs) can be obtained respectively, as Figure 4 shown, Figure 4 which is a scanning electron microscope image at a magnification of 30000 times. Figure 4It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution range is 1.19 - 1.34 μm.

[0057] Comparative Example 1: The difference from Example 1 is that glycerol was not added, and other steps and parameters are exactly the same as those in Example 1.

[0058] The product La-glycerate (La-gly) was obtained, as Figure 5 shown, Figure 5 is a scanning electron microscope image with a magnification of 35000 times. It can be seen that the material presents an irregular and agglomerated structure. It may be that when glycerol is not added, the interaction during the crystallization process of the substance is relatively strong, resulting in a more disordered morphology, unclear boundaries between particles, and this structure may affect the specific surface area, dispersibility and other properties of the material.

[0059] La2O3 microspheres (La2O3-SSs) were obtained, as Figure 6 shown, Figure 6 is a scanning electron microscope image with a magnification of 10000 times. It can be seen that although the particles are spherical, their sizes are not uniform, there are many small particles, and the surface is relatively rough, with obvious particle aggregation states. The particle size distribution range is 0.50 - 2.14 μm.

[0060] Comparative Example 2: The difference from Example 2 is that glycerol was not added, and other steps and parameters are exactly the same as those in Example 2.

[0061] The product Pr-glycerate (Pr-gly) was obtained, as Figure 7 shown, Figure 7 is a scanning electron microscope image with a magnification of 30000 times. It can be seen that when glycerol is not added, the substance presents an irregular agglomerated structure, the particles are adhered to each other, the boundaries are blurred, and the dispersibility is poor.

[0062] Pr2O3 microspheres (Pr2O3-SSs) were obtained, as Figure 8 shown, Figure 8 is a scanning electron microscope image with a magnification of 10000 times. It can be seen that the overall particles are spherical, but there are certain differences in size, the distribution is relatively dense, and there is a slight adhesion between some particles. The particle size distribution range is 0.51 - 2.79 μm.

[0063] Comparative Example 3: The difference from Example 1 is that 8 mL of glycerol and 56 mL of isopropyl alcohol (IPA) were stirred for half an hour to be fully mixed evenly, and 1.25 mmol of La(NO3)3·6H2O was stirred for 2 h to make La(NO3)3·6H2O evenly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 1.

[0064] The product La-glycerate (La-gly) was obtained, as Figure 9 shown Figure 9 is a scanning electron microscope image with a magnification of 2500 times. It can be seen that the details of individual particles can be clearly seen. The particles are spherical in shape, and the size is unevenly distributed, which is relatively obvious. The particle size distribution range is 0.78 - 4.26 μm, and there are subtle features on the surface of some particles.

[0065] La2O3 microspheres (La2O3-SSs) were obtained, as Figure 10 shown Figure 10 is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes are significantly different, the particle size distribution range is 0.59 - 2.51 μm, the distribution is chaotic, and some particles are agglomerated together.

[0066] Comparative Example 4: The difference from Example 1 is that 8 mL of glycerol and 56 mL of isopropanol (IPA) were stirred for half an hour to be fully mixed evenly, and 0.3125 mmol of La(NO3)3·6H2O was stirred for 2 h to make La(NO3)3·6H2O evenly dispersed in the mixed solution; other steps and parameters were exactly the same as those in Example 1.

[0067] The product La-glycerate (La-gly) was obtained, as Figure 11 shown Figure 11 is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the shape is not completely regular, some particles have a tendency to agglomerate, the overall distribution is dense and chaotic, and the particle size distribution range is 0.74 - 1.51 μm.

[0068] La2O3 microspheres (La2O3-SSs) were obtained, as Figure 12 shown Figure 12 is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes are significantly different, the shape is irregular, the distribution is chaotic and the agglomeration phenomenon is serious, and the particle size distribution range is 0.36 - 0.69 μm.

[0069] Comparative Example 5: The difference from Example 2 is that 8 mL of glycerol and 56 mL of isopropanol (IPA) were stirred for half an hour to be fully mixed evenly, and 1.25 mmol of Pr(NO3)3·6H2O was stirred for 2 h to make Pr(NO3)3·6H2O evenly dispersed in the mixed solution; other steps and parameters were exactly the same as those in Example 2.

[0070] The product Pr-glycerate (Pr-gly) was obtained, as Figure 13 shown Figure 13It is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particles are dense and of different sizes, and the distribution appears disorderly. Some particles overlap with each other, making it difficult to clearly distinguish the outline and details of individual particles. The particle size distribution range is 0.61 - 2.86 um.

[0071] Pr2O3 microspheres (Pr2O3-SSs) were obtained, as Figure 14 shown Figure 14 It is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle agglomeration phenomenon is serious, and the particles adhere to each other. The particle size distribution range is 0.82 - 2.56 um.

[0072] Comparative Example 6: The difference from Example 2 is that 8 mL of glycerol and 56 mL of isopropanol (IPA) were stirred for half an hour to be fully mixed evenly, and 0.3125 mmol of Pr(NO3)3·6H2O was stirred for 2 h to make Pr(NO3)3·6H2O evenly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 2.

[0073] The product Pr-glycerate (Pr-gly) was obtained, as Figure 15 shown Figure 15 It is a scanning electron microscope image with a magnification of 15000 times. It can be seen that there are certain differences in particle sizes, some particle shapes are not perfect spheres, and there is a slight aggregation phenomenon. The particle size distribution range is 0.68 - 0.93 um.

[0074] Pr2O3 microspheres (Pr2O3-SSs) were obtained, as Figure 16 shown Figure 16 It is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes are different, the distribution is dense and disorderly, and there is an obvious aggregation phenomenon. The particle size distribution range is 0.23 - 1.53 um.

[0075] Comparative Example 7: The difference from Example 1 is that 8 mL of glycerol and 48 mL of isopropanol (IPA) were stirred for half an hour to be fully mixed evenly, and other steps and parameters are exactly the same as those in Example 1.

[0076] The product La-glycerate (La-gly) was obtained, as Figure 17 shown Figure 17 It is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes are uneven, the shapes are not regular enough, some particles agglomerate together, and the dispersibility is poor. The particle size distribution range is 0.84 - 1.64 um.

[0077] La2O3 microspheres (La2O3-SSs) were obtained, as Figure 18 shown Figure 18It is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particle morphology is disordered, the sizes are different, the agglomeration into clusters is prominent, and the particle size distribution range is 0.30 - 1.30 μm.

[0078] Comparative Example 8: The difference from Example 1 is that 8 mL of glycerol and 72 mL of isopropyl alcohol (IPA) are stirred for half an hour to be fully mixed evenly, and other steps and parameters are exactly the same as those in Example 1.

[0079] The product La-glycerate (La-gly) is obtained, as Figure 19 shown, Figure 19 It is a scanning electron microscope image with a magnification of 4,000 times. It can be seen that although the particles are roughly spherical, they are sparsely distributed, and there are irregular lumps in some areas, which may be impurities or insufficiently dispersed aggregates. The particle size distribution range is 1.19 - 2.49 μm.

[0080] La2O3 microspheres (La2O3-SSs) are obtained, as Figure 20 shown, Figure 20 It is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particle sizes are different, the size distribution range is relatively wide, the particle size distribution range is 0.64 - 1.99 μm, and some particles are agglomerated with each other, and the morphology is not regular enough.

[0081] Comparative Example 9: The difference from Example 2 is that 8 mL of glycerol and 48 mL of isopropyl alcohol (IPA) are stirred for half an hour to be fully mixed evenly, and other steps and parameters are exactly the same as those in Example 2.

[0082] The product Pr-glycerate (Pr-gly) is obtained, as Figure 21 shown, Figure 21 It is a scanning electron microscope image with a magnification of 5,000 times. It can be seen that the particle sizes are different, the distribution is loose and there is obvious agglomeration, some particles are adhered together, and the surface also appears relatively rough. The particle size distribution range is 0.83 - 2.81 μm.

[0083] Pr2O3 microspheres (Pr2O3-SSs) are obtained, as Figure 22 shown, Figure 22 It is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that there are large differences in particle sizes, and there are many small particles mixed with large particles. The particle size distribution range is 0.41 - 1.74 μm.

[0084] Comparative Example 10: The difference from Example 2 is that 8 mL of glycerol and 72 mL of isopropyl alcohol (IPA) are stirred for half an hour to be fully mixed evenly, and other steps and parameters are exactly the same as those in Example 1.

[0085] The product Pr-glycerate (Pr-gly) is obtained, as Figure 23 shown Figure 23 is a scanning electron microscope image at a magnification of 3000 times. It can be seen that the particle sizes are different, the distribution is sparse and the agglomeration phenomenon is obvious. Multiple particles aggregate together to form irregular lumps, and the particle size distribution range is 0.61 - 2.67 μm.

[0086] Pr2O3 microspheres (Pr2O3-SSs) are obtained, as Figure 24 shown Figure 24 is a scanning electron microscope image at a magnification of 10000 times. It can be seen that the particle size differences are obvious, the morphology is not regular enough, and there are many cases where particles adhere and agglomerate to each other. The particle size distribution range is 0.36 - 1.59 μm.

[0087] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing lanthanum trioxide / praseodymium trioxide microspheres, characterized in that: It includes the following steps: (1) Preparing a first mixed solution: stirring and mixing glycerol and isopropanol to obtain a first mixed solution; (2) preparing a second mixed solution: adding La(NO3)3·6H2O / Pr(NO3)3·6H2O to the prepared first mixed solution and stirring to make La(NO3)3·6H2O / Pr (NO3)3·6H2O uniformly dispersed in the first mixed solution, thereby preparing a second mixed solution; (3) heating the second mixed solution to react and preparing a white precipitate: after the second mixed solution is heated to react, it is cooled to room temperature to obtain a white precipitate; (4) Obtaining the product La-glycerate / Pr-glycerate: washing, centrifuging and drying the white precipitate to obtain the product La-glycerate / Pr-glycerate; (5) Preparing La2O3 microspheres / Pr2O3 microspheres: calcining the La-glycerate / Pr-glycerate to prepare La2O3 microspheres / Pr2O3 microspheres; In the step (1), the volume ratio of glycerol to isopropanol is 1:7; The concentration of La(NO3)3·6H2O / Pr (NO3)3·6H2O in the second mixed solution is 4g / L-5g / L; In the step (3), the second mixed solution is heated to a reaction temperature of 220° C. and a reaction time of 8 h; In the step (4), the drying temperature is 70°C; In the step (5), the calcination heating rate is 2 °C min -1 , heat to 900℃ and calcine in air for 5h.

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