Preparation method of lanthanum trioxide / praseodymium trioxide microspheres

Abstract

The invention discloses a preparation method of lanthanum trioxide / praseodymium trioxide microspheres. The preparation method comprises the following steps: uniformly stirring and mixing glycerol and isopropanol to prepare a first mixed solution; la (NO3) 3.6 H2O / Pr (NO3) 3.6 H2O is added into the prepared first mixed solution and stirred, so that La (NO3) 3.6 H2O / Pr (NO3) 3.6 H2O is uniformly dispersed in the first mixed solution, and a second mixed solution is prepared; 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, so as to obtain a product La-glycerate / Pr-glycerate, wherein the La-glycerate / Pr-glycerate is used as a raw material; and calcining the La-glycerate / Pr-glycerate, so as to obtain the La2O3 microsphere / Pr2O3 microsphere, and preparing the La2O3 microsphere / Pr2O3 microsphere from the La-glycerate / Pr-glycerate. The method is simple in process, easy to control, high in treatment efficiency and low in cost; and the obtained product is regular in morphology, uniform in size and good in dispersity.

Description

Technical Field

[0001] The invention relates to the field of rare earth oxide production, and in particular to a method for preparing lanthanum trioxide / praseodymium trioxide microspheres. Background Art

[0002] In many cutting-edge fields such as materials science and chemical engineering, lanthanum trioxide (La 2 O 3 ) and praseodymium trioxide (Pr 2 O 3 ) occupies a pivotal position due to its unique physical and chemical properties and has become a focal material in scientific research and industrial applications.

[0003] Lanthanum trioxide, as an important rare earth metal oxide, appears as a white powder. 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 generate lanthanum carbonate. Lanthanum trioxide has a wide range of uses, including in the fields of optical glass, ceramic capacitors, piezoelectric ceramics, and high-temperature superconducting materials.

[0004] Praseodymium trioxide is a yellow-green or dark brown amorphous powder or block, has hygroscopic properties, easily absorbs carbon dioxide in the air, is soluble in acid but insoluble in water. It is widely used in the fields of petrochemicals, ceramic materials, and glass manufacturing.

[0005] With the rapid development of science and technology, the performance requirements of lanthanum trioxide and praseodymium trioxide in various fields are becoming more and more stringent, requiring them not only to have higher purity, but also to have precise control over their microstructure and morphology. However, the current conventional preparation methods often seem to be unable to meet these stringent requirements and expose many problems.

[0006] At present, the synthesis of spherical lanthanum trioxide / praseodymium trioxide (La 2 O 3 / Pr 2 O 3 ) are mainly co-precipitation, spray drying and hard template methods. However, these methods face technical difficulties such as uneven product size, difficult control, complex process and the removal of the template often requires the use of strong acids and strong bases, resulting in cumbersome processes and harsh conditions. Summary of the invention

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

[0008] The present invention is implemented by the following technical scheme: a method for preparing lanthanum trioxide / praseodymium trioxide microspheres, which comprises 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(NO 3 ) 3 6H 2 O / Pr(NO 3 ) 3 6H 2 O stirring, so that La(NO 3 ) 3 6H 2 O / Pr (NO 3 ) 3 6H 2 O is uniformly dispersed in the first mixed solution to prepare 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) Obtaining La 2 O 3 Microsphere / Pr 2 O 3 Microspheres: La-glycerate / Pr-glycerate is calcined to prepare La 2 O 3 Microsphere / Pr 2 O 3 Microspheres.

[0009] Furthermore, in step (1), the volume ratio of glycerol to isopropanol is 1:7.

[0010] Furthermore, the second mixed solution contains La(NO 3 ) 3 6H 2 O / Pr (NO 3 ) 3 6H 2 The concentration of O is 4g / L-5g / L.

[0011] Furthermore, in step (3), the second mixed solution is heated to a reaction temperature of 220° C. and a reaction time of 8 h.

[0012] Furthermore, in the step (4), the drying temperature is 70°C.

[0013] Furthermore, in step (5), the calcination heating rate is 2 °C min -1 , heat to 900℃ and calcine in air for 5h.

[0014] Advantages of the present invention: The method of the invention has simple process, easy control, high processing efficiency and low cost; the obtained product has regular morphology, uniform size and good dispersibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 This is a scanning electron microscope image of La-gly prepared in Example 1; Figure 2 The La prepared in Example 1 2 O 3 Scanning electron microscopy images of microspheres; Figure 3 This is a scanning electron microscope image of Pr-gly prepared in Example 2; Figure 4 Pr prepared in Example 2 2 O 3 Scanning electron microscopy images of microspheres; Figure 5 This is a scanning electron microscope image of La-gly prepared in Comparative Example 1; Figure 6 La prepared in Comparative Example 1 2 O 3 Scanning electron microscopy images of microspheres; Figure 7 This is a scanning electron microscope image of Pr-gly prepared in Comparative Example 2; Figure 8 Pr prepared in Comparative Example 2 2 O 3 Scanning electron microscopy images of microspheres; Fig. 9 This is a scanning electron microscope image of La-gly prepared in Comparative Example 3; Fig.10 La prepared in Comparative Example 3 2 O 3 Scanning electron microscopy images of microspheres; Fig.11 This is a scanning electron microscope image of La-gly prepared in Comparative Example 4; Fig.12 La prepared in Comparative Example 42 O 3 Scanning electron microscopy images of microspheres; Fig.13 This is a scanning electron microscope image of Pr-gly prepared in Comparative Example 5; Fig.14 Pr prepared in Comparative Example 5 2 O 3 Scanning electron microscopy images of microspheres; Fig.15 This is a scanning electron microscope image of Pr-gly prepared in Comparative Example 6; Fig.16 Pr prepared in Comparative Example 6 2 O 3 Scanning electron microscopy images of microspheres; Fig.17 This is a scanning electron microscope image of La-gly prepared in Comparative Example 7; Fig.18 La prepared in Comparative Example 7 2 O 3 Scanning electron microscopy images of microspheres; Fig.19 This is a scanning electron microscope image of La-gly prepared in Comparative Example 8; Fig. 20 The La prepared in Comparative Example 8 2 O 3 Scanning electron microscopy images of microspheres; Fig.21 This is a scanning electron microscope image of Pr-gly prepared in Comparative Example 9; Fig. 22 Pr prepared in Comparative Example 9 2 O 3 Scanning electron microscopy images of microspheres; Fig.23 This is a scanning electron microscope image of Pr-gly prepared in Comparative Example 10; Fig.24 Pr prepared in Comparative Example 10 2 O 3 Scanning electron micrograph of microspheres. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in 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.

[0018] Example 1: A method for preparing lanthanum trioxide microspheres, comprising the following steps: (1) Preparation of lanthanum glycerate spheres 8 mL of glycerol and 56 mL of isopropanol (IPA) were stirred for half an hour to mix thoroughly. 0.625 mmol La(NO 3 ) 3 6H 2 O was stirred for 2 h to make La(NO 3 ) 3 6H 2 O is evenly dispersed in the mixed solution; the mixed solution is poured into a 100 mL reactor and placed in a forced air drying oven at 220 °C for 8 h; after the reactor cools to room temperature, the white precipitate is taken out and washed with anhydrous ethanol three times, the product obtained by centrifugation is placed in a 70 °C vacuum drying oven for drying, and finally the product La-glycerate (La-gly) is obtained, such as Figure 1 As shown, Figure 1 This is a scanning electron microscope image with a magnification of 2000 times. Figure 1 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution range is 1.1-2.0um.

[0019] (2) Preparation of lanthanum trioxide microspheres The La-gly / Pr-gly obtained in step (1) was placed in a muffle furnace at 2 °C min -1 The heating rate was calcined at 900℃ in air for 5 h and then naturally cooled to room temperature to obtain La 2 O 3 Microspheres (La 2 O 3 -SSs), such as Figure 2 As shown, Figure 2 This is a scanning electron microscope image with a magnification of 22,000 times. Figure 2 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution range is 1.43-1.55um.

[0020] Example 2: A method for preparing praseodymium trioxide microspheres, comprising the following steps: (1) Preparation of praseodymium glycerate spheres 8 mL of glycerol and 56 mL of isopropyl alcohol (IPA) were stirred for half an hour to mix thoroughly. 0.625 mmol Pr(NO 3 ) 3 6H 2 O for 2 h to make Pr(NO 3 ) 3 6H 2O is evenly dispersed in the mixed solution; the mixed solution is poured into a 100 mL reactor and placed in a forced air drying oven at 220 °C for 8 h; after the reactor cools to room temperature, the white precipitate is taken out and washed with anhydrous ethanol three times, the product obtained by centrifugation is placed in a 70 °C vacuum drying oven for drying, and finally the product Pr-glycerate (Pr-gly) is obtained, such as Figure 3 As shown, Figure 3 This is a scanning electron microscope image with a magnification of 10,000 times. Figure 3 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution range is 1.63-1.99um.

[0021] (2) Preparation of praseodymium trioxide microspheres The Pr-gly obtained in step (1) was placed in a muffle furnace at 2 °C min -1 The heating rate was calcined at 900 ℃ in air for 5 h and then naturally cooled to room temperature to obtain Pr 2 O 3 Microspheres (Pr 2 O 3 -SSs), such as Figure 4 As shown, Figure 4 This is a scanning electron microscope image with a magnification of 30,000 times. Figure 4 It can be seen that the obtained product has regular morphology, uniform size, good dispersibility, and the particle size distribution range is 1.19-1.34um.

[0022] Comparative Example 1: The difference from Example 1 is that no glycerol is added, and the other steps and parameters are exactly the same as those of Example 1.

[0023] The product La-glycerate (La-gly) is obtained, such as Figure 5 As shown, Figure 5 This is a scanning electron microscope image with a magnification of 35,000 times. It can be seen that the material has an irregular, agglomerated structure. It may be that when glycerol is not added, the interaction between the substances during the crystallization process is strong, resulting in a more disordered morphology and unclear boundaries between particles. This structure may affect the material's specific surface area, dispersibility and other properties.

[0024] Get La 2 O 3 Microspheres (La 2 O 3 -SSs), such as Figure 6 As shown, Figure 6 This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that although the particles are spherical, they are uneven in size, there are many small particles, and the surface is relatively rough. There is obvious particle aggregation, and the particle size distribution range is 0.50-2.14um.

[0025] Comparative Example 2: The difference from Example 2 is that no glycerol is added, and the other steps and parameters are exactly the same as those of Example 2.

[0026] The product Pr-glycerate (Pr-gly) is obtained, such as Figure 7 As shown, Figure 7 This is a scanning electron microscope image with a magnification of 30,000 times. It can be seen that when no glycerol is added, the material presents an irregular agglomerated structure, the particles are adhered to each other, the boundaries are blurred, and the dispersion is poor. Get Pr 2 O 3 Microspheres (Pr 2 O 3 -SSs), such as Figure 8 As shown, Figure 8 This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particles are spherical as a whole, but there are certain differences in size and the distribution is relatively dense. Some particles are slightly adhered to each other. The particle size distribution range is 0.51-2.79um.

[0027] 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 mix well, and 1.25 mmol La(NO 3 ) 3 6H 2 O was stirred for 2 h to make La(NO 3 ) 3 6H 2 O is uniformly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 1.

[0028] The product La-glycerate (La-gly) is obtained, such as Fig. 9 As shown, Fig. 9 This 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. It can be observed that the particles are spherical and the size is more uneven. The particle size distribution range is 0.78-4.26um, and some particles have subtle features on the surface.

[0029] Get La 2 O 3 Microspheres (La 2 O 3 -SSs), such as Fig.10 As shown, Fig.10 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes are obviously different. The particle size distribution range is 0.59-2.51um. The distribution is disorderly and some particles are agglomerated together.

[0030] Comparative Example 4: 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, and 0.3125 mmol of La(NO 3 ) 3 6H 2 O was stirred for 2 h to make La(NO 3 ) 3 6H 2 O is uniformly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 1.

[0031] The product La-glycerate (La-gly) is obtained, such as Fig.11 As shown, Fig.11 This 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 disorderly, and the particle size distribution range is 0.74-1.51um.

[0032] Get La 2 O 3 Microspheres (La 2 O 3 -SSs), such as Fig.12 As shown, Fig.12 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle sizes vary significantly, the shapes are irregular, the distribution is disorderly, and the agglomeration phenomenon is serious. The particle size distribution range is 0.36-0.69um.

[0033] Comparative Example 5: The difference from Example 2 is that 8 mL of glycerol and 56 mL of isopropyl alcohol (IPA) were stirred for half an hour to mix well, and 1.25 mmol Pr (NO 3 ) 3 6H 2 O was stirred for 2 h to make Pr (NO 3 ) 3 6H 2 O is uniformly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 2.

[0034] The product Pr-glycerate (Pr-gly) is obtained, such as Fig.13 As shown, Fig.13 This 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, the distribution appears messy, and 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 0.61-2.86um.

[0035] Get Pr 2 O 3 Microspheres (Pr2 O 3 -SSs), such as Fig.14 As shown, Fig.14 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particles are seriously agglomerated and adhere to each other. The particle size distribution range is 0.82-2.56um.

[0036] Comparative Example 6: The difference from Example 2 is that 8 mL of glycerol and 56 mL of isopropyl alcohol (IPA) were stirred for half an hour to mix well, and 0.3125 mmol Pr (NO 3 ) 3 6H 2 O was stirred for 2 h to make Pr (NO 3 ) 3 6H 2 O is uniformly dispersed in the mixed solution; other steps and parameters are exactly the same as those in Example 2.

[0037] The product Pr-glycerate (Pr-gly) is obtained, such as Fig.15 As shown, Fig.15 This is a scanning electron microscope image with a magnification of 15,000 times. It can be seen that there are certain differences in particle size. The shape of some particles is not a perfect sphere, and there is slight aggregation. The particle size distribution range is 0.68-0.93um.

[0038] Get Pr 2 O 3 Microspheres (Pr 2 O 3 -SSs), such as Fig.16 As shown, Fig.16 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particles are of different sizes, densely and disorderly distributed, and there is obvious agglomeration. The particle size distribution range is 0.23-1.53um.

[0039] Comparative Example 7: The difference from Example 1 is that 8 mL of glycerol and 48 mL of isopropyl alcohol (IPA) are stirred for half an hour to be fully mixed, and the other steps and parameters are exactly the same as those in Example 1.

[0040] The product La-glycerate (La-gly) is obtained, such as Fig.17 As shown, Fig.17 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particle size is uneven, the shape is irregular, some particles are agglomerated together, and the dispersion is poor. The particle size distribution range is 0.84-1.64um.

[0041] Get La 2 O 3 Microspheres (La2 O 3 -SSs), such as Fig.18 As shown, Fig.18 This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particles are in disordered shape, of varying sizes, and are prominently clustered. The particle size distribution range is 0.30-1.30um.

[0042] 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, and the other steps and parameters are exactly the same as those in Example 1.

[0043] The product La-glycerate (La-gly) is obtained, such as Fig.19 As shown, Fig.19 This is a scanning electron microscope image with a magnification of 4000 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 inadequately dispersed agglomerates. The particle size distribution range is 1.19-2.49um.

[0044] Get La 2 O 3 Microspheres (La 2 O 3 -SSs), such as Fig. 20 As shown, Fig. 20 This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particles are of different sizes and the size distribution range is wide. The particle size distribution range is 0.64-1.99um, and some particles are agglomerated with each other and the shape is not regular.

[0045] 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, and the other steps and parameters are exactly the same as those in Example 2.

[0046] The product Pr-glycerate (Pr-gly) is obtained, such as Fig.21 As shown, Fig.21 This is a scanning electron microscope image with a magnification of 5000 times. It can be seen that the particles are of different sizes, loosely distributed and have obvious agglomeration. Some particles are stuck together and the surface appears to be relatively rough. The particle size distribution range is 0.83-2.81um.

[0047] Get Pr 2 O 3 Microspheres (Pr 2 O 3 -SSs), such as Fig. 22 As shown, Fig. 22This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particle sizes vary greatly, with a large number of small particles mixed with large particles. The particle size distribution range is 0.41-1.74um.

[0048] 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, and the other steps and parameters are exactly the same as those in Example 1.

[0049] The product Pr-glycerate (Pr-gly) is obtained, such as Fig.23 As shown, Fig.23 This is a scanning electron microscope image with a magnification of 3000 times. It can be seen that the particles are of different sizes, sparsely distributed and obviously agglomerated. Multiple particles gather together to form irregular agglomerates. The particle size distribution range is 0.61-2.67um.

[0050] Get Pr 2 O 3 Microspheres (Pr 2 O 3 -SSs), such as Fig.24 As shown, Fig.24 This is a scanning electron microscope image with a magnification of 10,000 times. It can be seen that the particle sizes are obviously different, the shapes are irregular, and there are many particles adhering to and agglomerating with each other. The particle size distribution range is 0.36-1.59um.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should 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.

2. The method for preparing lanthanum trioxide / praseodymium trioxide microspheres according to claim 1, characterized in that: In the step (1), the volume ratio of glycerol to isopropanol is 1:

7.

3. The method for preparing lanthanum trioxide / praseodymium trioxide microspheres according to claim 1, characterized in that: The concentration of La(NO3)3·6H2O / Pr(NO3)3·6H2O in the second mixed solution is 4g / L-5g / L.

4. The method for preparing lanthanum trioxide / praseodymium trioxide microspheres according to claim 1, characterized in that: In the step (3), the second mixed solution is heated to a reaction temperature of 220° C. and a reaction time of 8 h.

5. The method for preparing lanthanum trioxide / praseodymium trioxide microspheres according to claim 1, characterized in that: In the step (4), the drying temperature is 70°C.

6. The method for preparing lanthanum trioxide / praseodymium trioxide microspheres according to claim 1, characterized in that: 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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