Preparation method of nano rare earth fluoride with special morphology

Abstract

The invention provides a preparation method of nano rare earth fluoride with special morphology, and relates to the technical field of rare earth fluoride preparation. The method comprises the following steps: firstly, dissolving rare earth salt with deionized water, then adding a morphology modifier and stirring, and further adding a precipitant solution and stirring to obtain a rare earth-based turbid liquid; transferring the obtained turbid liquid into a homogeneous reactor for reaction; after the reaction is finished, performing liquid-solid separation to extract precipitates in the turbid liquid, and performing water-alcohol alternate washing; drying the precipitate in a vacuum drying oven to obtain loose powder as a precursor; and finally, roasting the precursor in a tubular furnace to obtain the product rare earth fluoride. The method is simple to operate and good in repeatability, and the obtained rare earth fluoride product is special in morphology, uniform in particle distribution, good in dispersity and high in stability; the material can be applied to the photoelectron field and biomedicine, and can be used as a catalyst carrier and a filler to improve the wear resistance and high temperature resistance of polymers / ceramics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rare earth fluoride preparation, in particular to a preparation method of special morphology nanometer rare earth fluoride. BACKGROUND

[0002] China has rich reserves of rare earth, accounting for about 88% of the world's total reserves, and the development and production of various rare earth products are increasing year by year. With the development of the country and the progress of science and technology, China's rare earth industry has entered a stage of rapid development. Rare earth fluoride has attracted widespread attention due to its good hygroscopicity, resistance to hydrolysis, and good stability in air.

[0003] At present, the preparation process of rare earth fluoride includes precipitation method, microemulsion method, hydrothermal and solvothermal method, and sol-gel method. The existing patents show that Miao Ruiying et al. use hydroxy ether solvent coordination, use fluorine-containing ionic liquid for precipitation, and finally use water and ethanol for washing. This method does not perform calcination process, and the obtained product XRD peak position is slightly shifted, indicating that there may be crystal water in it. The method described by Yan Xiaohong et al. uses rare earth oxide to dissolve into rare earth salt solution, and adds a precipitating agent to obtain rare earth fluoride. The use of rare earth oxide in this method is less economical than the use of rare earth salt solution. Huang Zhen et al. use multiple hydrogenation and dehydrogenation operations to obtain low water oxygen rare earth fluoride. This method cannot control the morphology and has high requirements for the operation equipment. Du Yongliang et al. add rare earth chloride, fluorination agent and anion coagulant to the rare earth carbonate solution to obtain rare earth fluoride. This method has the problem of uncontrollable morphology in the preparation process.

[0004] In the field of material science, the properties of materials are closely related to the morphology, size and dimension of the crystal, so it is of great significance to control the synthesis of materials to a specific morphology and size. The properties of rare earth fluoride nanomaterials are mainly determined by their structure, morphology and size. Different preparation processes can be used to obtain rare earth fluoride nanomaterials with different morphologies and sizes. SUMMARY

[0005] In order to solve the above technical problems existing in the prior art, the present application provides a preparation method of special morphology nanometer rare earth fluoride. The method dissolves a salt containing rare earth elements in deionized water, then adds a morphology modifier to the rare earth salt solution, and finally adds a fluorine-containing ion solution to the above mixed solution. At a certain temperature, the salt containing rare earth elements reacts with fluorine ions to obtain rare earth fluoride with special morphology. The technical solution is as follows: A preparation method of special morphology nanometer rare earth fluoride, the method comprises: S1, dissolve rare earth salt and morphology modifier in deionized water to form uniform rare earth salt solution and morphology modifier solution; S2, adding a morphology modifier solution to the rare earth salt solution and stirring, and then adding a precipitant solution to the mixed solution and stirring to obtain a rare earth-based suspension; S3, transferring the obtained suspension into a homogeneous reactor for reaction; S4, after the reaction, performing liquid-solid separation, extracting the precipitate in the suspension and performing water-alcohol alternate washing; S5, placing the washed precipitate into a vacuum drying oven for drying to obtain a loose powder, the loose powder being a precursor; S6, placing the precursor into a tube furnace for temperature-controlled calcination to obtain a product, rare earth fluoride.

[0006] The rare earth salt in S1 is one or more of a rare earth chloride salt, a rare earth nitrate salt or a rare earth sulfate salt, and the concentration of the rare earth salt solution is 0.1-4 mol / L.

[0007] The rare earth salt is one or more of DyCl3, NdCl3, YCl3 and La(NO3)3.

[0008] The morphology modifier in S1 is one or a combination of citric acid, urea, tartaric acid, gallic acid and acetamide, and the concentration of the morphology modifier solution is 0.05-12 mol / L. The molar ratio of the morphology modifier to the rare earth salt in S2 is 0.5:1-3:1.

[0009] The precipitant in S2 is one or two of sodium fluoride, ammonium fluoride and hydrogen fluoride, and the amount of the precipitant added is 0.5-6 mol / L.

[0010] The feeding speed of the precipitant solution in S2 is 0.5-6 ml / min, and the stirring speed for adding the precipitant solution is 200-500 rpm. Generally, a peristaltic pump is used for dropwise addition.

[0011] The reaction temperature in S3 is 120-200℃, and the reaction time is 2-24 hours.

[0012] In S4, generally, suction filtration or centrifugal separation is used for liquid-solid separation, and after the separation, the precipitate is washed with water-ethanol alternately for 3 times.

[0013] The vacuum drying temperature in S5 is 40-80℃, and the drying time is 12-24 hours.

[0014] The calcination in S6 is performed in an inert atmosphere, the calcination temperature is 500-600℃, and the calcination time is 2-8 hours. The rare earth fluoride prepared in S6 has a star-prism or carambola shape.

[0015] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects: In the above scheme, at a certain temperature, the salt containing rare earth elements reacts with fluoride ions, the reaction environment is liquid, the reaction contact area is relatively large, so that the reaction is complete, and finally sintering is carried out, so that the water in the product is better removed, the water content of the product is low, and the purity is high. The method is simple to operate and has good repeatability. The obtained rare earth fluoride product has a special star prism or carambola shape, uniform particle distribution, good dispersibility and high stability. It can be applied in the field of optoelectronics, biomedicine, as a catalyst carrier, and as a filler to improve the wear resistance and high temperature resistance of polymers / ceramics. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 It is a preparation method flow chart of a special morphology nanometer rare earth fluoride provided by the embodiment of the present application; Figure 2 It is an XRD graph of the precursor YF3 prepared in embodiment 1 of the present application; Figure 3 It is an XRD graph of YF3 prepared in embodiment 1 of the present application; Figure 4 It is an SEM graph of YF3 prepared in embodiment 1 of the present application; Figure 5 It is an XRD graph of the precursor YF3 prepared in embodiment 2 of the present application; Figure 6 It is an XRD graph of YF3 prepared in embodiment 2 of the present application; Figure 7 It is an SEM graph of YF3 prepared in embodiment 2 of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the present application will be described below in combination with the drawings.

[0019] In the embodiments of the present application, the words such as "example", "for example" are used to represent as an example, illustration or description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be one of the two.

[0020] In the embodiments of the present application, sometimes the subscript such as W1 can be written in the form of non-subscript such as W1, and the meanings expressed thereby are consistent when the difference is not emphasized.

[0021] To make the technical problems, technical solutions and advantages to be solved by the present application more clear, the following will be described in detail with reference to the drawings and specific embodiments.

[0022] The embodiments of the present application provide a preparation method of special morphology nanometer rare earth fluoride. Figure 1 As shown in the flow chart of the preparation method of special morphology nanometer rare earth fluoride, the method can include the following steps: S1, dissolving the rare earth salt and the morphology modifier in deionized water respectively to form a uniform rare earth salt solution and a morphology modifier solution; S2, adding the morphology modifier solution to the rare earth salt solution and stirring, and then adding a precipitant solution to the mixed solution and stirring to obtain a rare earth-based suspension; S3, transferring the obtained suspension into a homogeneous reactor for reaction; S4, after the reaction, performing liquid-solid separation, extracting the precipitate in the suspension and performing water-alcohol alternating washing; S5, placing the washed precipitate into a vacuum drying box for drying to obtain a loose powder, and the loose powder is a precursor; S6, placing the precursor into a tube furnace for temperature control roasting to obtain a product of rare earth fluoride.

[0023] The following will be described with reference to specific embodiments.

[0024] Embodiment 1

[0025] 3.0339g of yttrium chloride was weighed and dissolved in 100ml of deionized water to prepare a yttrium fluoride solution with a concentration of 0.1mol / L, and stirred for 10 minutes to fully dissolve to obtain a uniform solution; 0.7503g of tartaric acid was weighed and dissolved in 50ml of deionized water to prepare a tartaric acid solution with a concentration of 0.1mol / L, and stirred for 10 minutes to fully dissolve to form a uniform solution; 3.7036g of ammonium fluoride was weighed and dissolved in 100ml of deionized water to prepare an ammonium fluoride solution with a concentration of 1mol / L, and stirred for 10 minutes to fully dissolve to obtain a uniform solution.

[0026] 50ml of the yttrium chloride solution and 50ml of the tartaric acid solution were fully mixed to obtain a uniform solution, and constant temperature stirring was maintained at 25℃ during the preparation and mixing process.

[0027] Take 15 ml of ammonium fluoride solution using a peristaltic pump at a rate of 0.5 ml / min into the mixed solution of yttrium chloride and tartaric acid, after the completion of the dropwise addition, stir for 30 minutes, get the suspension.

[0028] The suspension is transferred to the PPL lining of the homogeneous reactor, and the reaction is carried out at a reaction temperature of 150℃ in the homogeneous reactor for 6 hours. After cooling, take out and filter, wash with ethanol and deionized water alternately for 3 times, and dry the filtered precipitate in a vacuum drying oven at 80℃ for 12 hours to obtain 0.7200 g of the precursor. Take out 0.4414 g of the precursor, use a tube furnace, sinter at 500℃ for 5 hours under argon atmosphere, and obtain 0.4185 g of the reaction product.

[0029] Figure 2 The XRD pattern of the reaction precursor is shown in FIG. 1. Figure 2 As shown in FIG. 1, the bottom line is the standard PDF card of YF3, and the upper black line is the XRD pattern of the reaction precursor. After comparison, the precipitate is YF3, but the peak position is slightly offset. There is crystal water in the precursor, and the crystal water molecules embedded in the crystal structure will increase the unit cell parameter, resulting in an increase in the interplanar spacing, thereby causing the peak position to shift.

[0030] Figure 3 The XRD pattern of the reaction product is shown in FIG. 2. Figure 3 As shown in FIG. 2, the bottom line is the standard PDF card of YF3, and the upper black line is the XRD pattern of the reaction product. After comparison, the product is YF3, and the peak position does not shift.

[0031] Figure 4 The SEM image of the reaction product is shown in FIG. 3. Figure 4 As shown in FIG. 3, the YF3 prepared by the method is a carambola shape, and the grain size is 700-800 nm after particle size statistics. It can be seen that the YF3 prepared by the method has a small particle size of nanoscale and a special morphology.

[0032] Example 2

[0033] Take 3.0336 g of yttrium chloride and dissolve it in 100 ml of deionized water, stir for 10 minutes, and fully dissolve to obtain a uniform solution; Take 0.7505 g of tartaric acid and dissolve it in 50 ml of deionized water, stir for 10 minutes, and fully dissolve to form a uniform solution; Prepare a 1 mol / L HF solution, stir for 10 minutes, and fully dissolve to obtain a uniform solution.

[0034] Take 50 ml of yttrium chloride solution and 50 ml of tartaric acid solution and mix them thoroughly to obtain a uniform solution. Keep the temperature at 25℃ during the preparation and mixing process.

[0035] 15 ml of HF solution was added dropwise to a mixed solution of yttrium chloride and tartaric acid at a rate of 0.5 ml / min using a peristaltic pump. After the addition was complete, the mixture was stirred for 30 minutes to obtain a suspension. The suspension was transferred to a homogeneous reactor lined with PPL and reacted at 150 °C for 6 hours. After cooling, the mixture was filtered and washed three times alternately with deionized water. The precipitate was then dried in a vacuum drying oven at 80 °C for 12 hours to obtain 0.6 g of the precursor. 0.2898 g of the precursor was taken out and sintered in a tube furnace at 500 °C for 5 hours under an argon atmosphere to obtain 0.2526 g of the reaction product.

[0036] Figure 5 This is the XRD pattern of the reaction precursor. (Example:) Figure 5 As shown, the bottom line represents the standard PDF card of YF3, and the upper black line represents the XRD pattern of the reaction precursor. After comparison, the precipitate is confirmed to be YF3. However, the peak position is slightly shifted to a lower angle, which should indicate the presence of water of crystallization in YF3.

[0037] Figure 6 The image shows the XRD pattern of the reaction products. (Example:) Figure 6 As shown, the bottom line represents the standard PDF card for YF3, and the upper black line represents the XRD pattern of the reaction product. Comparison confirmed that the precipitate is YF3, with better crystallinity.

[0038] Figure 7 This is a SEM image of the reaction products. (Example:) Figure 7 As shown, the YF3 prepared by this method is star-shaped, and the grain size is 550-650 nm after particle size statistics. It can be seen that the YF3 prepared by the method of this application has a small particle size, which is nanoscale, and has a special morphology.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing rare earth nano-fluorides with special morphology, characterized in that, The method includes: S1. Dissolve the rare earth salt and the morphology modifier separately in deionized water to form a homogeneous rare earth salt solution and a morphology modifier solution. S2. Add morphology modifier solution to rare earth salt solution and stir, then add precipitant solution to mixed solution and stir to obtain rare earth-based suspension; S3. Transfer the resulting suspension to a homogeneous reactor for reaction; S4. After the reaction, liquid-solid separation is performed to extract the precipitate from the suspension and wash it with water and alcohol alternately. S5. Place the washed precipitate into a vacuum drying oven and dry it to obtain a loose powder, which is the precursor. S6. The precursor is placed in a tube furnace for controlled-temperature calcination to obtain the rare earth fluoride product.

2. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The rare earth salt in S1 is one or more of rare earth chloride, rare earth nitrate or rare earth sulfate, and the concentration of the rare earth salt solution is 0.1~4 mol / L.

3. The method for preparing special morphology nano-rare earth fluorides according to claim 2, characterized in that, The rare earth salt is one or more of DyCl3, NdCl3, YCl3, and La(NO3)3.

4. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The morphology modifier in S1 is one or a combination of citric acid, urea, tartaric acid, gallic acid, and acetamide, and the concentration of the morphology modifier solution is 0.05~12 mol / L; The molar ratio of morphology modifier to rare earth salt in S2 is 0.5:1 to 3:

1.

5. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The precipitant in S2 is one or two of sodium fluoride, ammonium fluoride, and hydrogen fluoride, and the amount of precipitant added is 0.5~6 mol / L.

6. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The feeding rate of the precipitant solution in S2 is 0.5~6 ml / min, and the stirring speed of the precipitant solution is 200~500 rpm.

7. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The reaction temperature in S3 is 120~200℃, and the reaction time is 2~24 hours.

8. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, During the liquid-solid separation in S4, the precipitate is washed three times alternately with water and ethanol.

9. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The vacuum drying temperature in S5 is 40~80℃, and the drying time is 12~24 hours.

10. The method for preparing special morphology nano-rare earth fluorides according to claim 1, characterized in that, The calcination in S6 is carried out under an inert atmosphere, at a temperature of 500-600℃, and for 2-8 hours. The rare earth fluoride obtained in S6 has a star-shaped or starfruit-shaped morphology.

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