Na3scf6 and a method for preparing the same

Abstract

The application discloses Na3ScF6 and a preparation method thereof, and belongs to the technical field of new material preparation. The method comprises the following steps: fluorination of Sc2O3, chemical reaction, filtration and drying. In the method, the surface activity of the powder is improved by the plasma ball milling, the chemical reaction is promoted, the fluorination rate of the Sc2O3 is improved, the strong alkali reaction of the NaOH is utilized to perform ion exchange, and the Na3ScF6 with high yield and high purity is obtained. The preparation method is simple and convenient to operate.

Description

Technical Field

[0001] This invention belongs to the field of new material preparation technology, specifically relating to a Na3ScF6 and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Sodium fluoroscandium (Na3ScF6) is a novel rare-earth chemical material. Compared with traditional rare-earth metals, it possesses advantages such as chemical stability, high-temperature strength, and corrosion resistance. Adding Na3ScF6 to coatings can produce fluoropolymer coatings, which exhibit high-temperature resistance, acid and alkali corrosion resistance, and aging resistance, making them excellent anti-corrosion coatings. In the papermaking process, adding a certain proportion of Na3ScF6 to the pulp can reduce the paper's absorption of water and organic solvents, and give the paper good water resistance, high-temperature resistance, and aging resistance. In the petrochemical field, Na3ScF6 exhibits strong catalytic activity and excellent high-temperature resistance in hydrocracking catalysts, effectively extending catalyst lifespan while improving product quality and yield. In the electronics industry, Na3ScF6 can be used as a conductive agent in semiconductor manufacturing, effectively improving the electrical properties of semiconductors, enhancing their conductivity, and improving the reliability of electronic components. In the aerospace industry, Na3ScF6 can be used as a high-temperature resistant and high-strength material; in the missile industry, Na3ScF6 can be used as a radiation shielding material and an electromagnetic interference resistant material.

[0004] In recent years, with the increasing application fields of Na3ScF6, its demand has also grown rapidly. Currently, the preparation methods of Na3ScF6 include chemical coprecipitation, solvothermal method, and hydrothermal method.

[0005] The main principle of the chemical coprecipitation method is to use sodium fluoride as a raw material, add a certain concentration of HF acid and NH4Cl, and generate Na3ScF6 precipitate through a chemical reaction at a certain temperature. The advantages of this method are fast reaction speed, effective control of raw material ratio and temperature during preparation, low reaction temperature, low equipment investment, low energy consumption, and high product purity. The disadvantage is that this method uses the hazardous and corrosive liquid HF acid, which poses a significant environmental hazard.

[0006] The solvothermal method refers to a process in which one or more solutes are dissolved in a solvent at high temperatures, and then the solutes are precipitated from the solvent by controlling the temperature and time to obtain the desired product. This method offers advantages such as high yield, simple process, and environmental friendliness in fluoride preparation. However, its disadvantages include high reaction temperatures, long reaction times, low purity of the resulting fluorides, and a tendency to agglomerate. Liu et al. used a solvothermal method to prepare Na3ScF6, with a reaction temperature of 500℃ and a reaction time as long as 6 hours.

[0007] The hydrothermal method controls the crystal form and structure of the product by controlling conditions such as reaction time, temperature, and pH. The product produced by the hydrothermal method is a single crystalline phase, but the morphology of the product is affected by the product type and growth conditions during the hydrothermal process, and its preparation conditions are relatively harsh.

[0008] Considering the characteristics of various methods, the chemical coprecipitation method is relatively mature, but it requires hazardous corrosive liquids; the solvothermal method requires high reaction temperatures and is costly, producing fluorides with low purity and prone to agglomeration; the hydrothermal method for preparing Na3ScF6 requires readily available raw materials, but it still has shortcomings for producing high-purity, high-crystallinity Na3ScF6 products, mainly due to high production costs and harsh reaction conditions. Therefore, there is an urgent need to develop new methods for preparing Na3ScF6 to overcome these problems. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing Na3ScF6. This invention utilizes scandium oxide as a raw material and obtains high-purity Na3ScF6 through a room-temperature chemical co-precipitation method, which is low-cost and simple to operate.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] In a first aspect, the present invention provides a method for preparing Na3ScF6, comprising the following steps:

[0012] (1) Scandium oxide and ammonium fluoride were placed in a ball mill jar under protective gas and subjected to plasma ball milling to obtain a prefluorinated compound (NH4). x ScF y Mixed powders;

[0013] (2) The mixed powder is stirred at a constant temperature to obtain (NH4)3ScF6;

[0014] (3) Add sodium hydroxide solution to the obtained (NH4)3ScF6, heat and stir to obtain a sodium salt mixture;

[0015] (4) Wash and dry the sodium salt mixture to obtain Na3ScF6.

[0016] In some embodiments of the present invention, the mass ratio of scandium oxide to ammonium fluoride is 1:1.5 to 6.

[0017] This invention involves placing Sc2O3 and NH4HF2 in a ball mill jar filled with a protective gas at a certain mass ratio, and performing plasma ball milling. The protective gas plasma is used to activate the surface of the Sc2O3 and NH4HF2 powders, followed by mixing and fluorination to obtain a pre-fluorinated compound (NH4). x ScF y The mixture of powders. Among them, plasma ball milling technology utilizes plasma to activate the powder surface, reduce surface tension, and improve the fluorination rate of Sc2O3.

[0018] In some embodiments of the present invention, the plasma ball milling conditions are as follows: ball-to-material mass ratio of 5 to 20:1, isostatic discharge frequency of 5 to 25 kHz, rotation speed of 500 to 2000 rpm, and ball milling time of 5 to 60 min.

[0019] In some embodiments of the present invention, the protective gas includes, but is not limited to, nitrogen and argon.

[0020] In some embodiments of the present invention, in step (2), the constant temperature stirring is performed at a temperature of 50–100°C for a time of 2–10 hours. Furthermore, a specific instrument can be used for constant temperature stirring, such as a constant temperature heating magnetic stirrer, which can ensure the temperature of the chemical reaction between the compounds and also increase the reaction rate, thereby realizing the reaction of Sc2O3 with NH4HF2 to generate the specific fluoride (NH4)3ScF6.

[0021] In some embodiments of the present invention, in step (3), an excess of sodium hydroxide solution is added. The sodium hydroxide solution is added, utilizing [OH... - [NH4] in solution + The reaction occurs, completing [Na] + ] and [NH4 + The exchange of [Na] produces Na3ScF6. To improve the yield of Na3ScF6, the [Na] in the solution... + ] and [ScF6 3- The molar ratio of sodium hydroxide solution to sodium hydroxide solution is greater than or equal to 3, indicating that sodium hydroxide solution has been added in excess.

[0022] In some embodiments of the present invention, in step (3), the heating and stirring are performed at a frequency of 100–500 rpm and a temperature of 50–80°C for 2–6 hours. Furthermore, specific instruments, such as a constant-temperature magnetic stirrer, can be used for heating and stirring.

[0023] In some embodiments of the present invention, in step (4), the washing is performed by washing the sodium salt mixture with pure water.

[0024] In some embodiments of the present invention, the washing process can be repeated multiple times, preferably 3 to 5 times. After washing, the sodium salt can be obtained by vacuum filtration using a circulating water pump. The purpose of washing and filtration is to remove water-soluble impurities from the sodium salt mixture during washing. The more times the mixture is washed, the more impurities are removed, and the higher the purity of the target product obtained.

[0025] In some embodiments of the present invention, in step (4), the drying is carried out at a temperature of 50 to 150°C for 1 to 2 hours until constant weight is obtained, thus yielding Na3ScF6.

[0026] In a second aspect, the present invention provides a Na3ScF6 prepared by the above-described preparation method.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention discloses a method for preparing Na3ScF6, comprising the following steps: placing scandium oxide and ammonium hydrofluoride into a ball mill jar under protective gas protection, and performing plasma ball milling to obtain a prefluorinated compound.

[0029] (NH4) x ScF y The mixed powder is stirred at a constant temperature to obtain (NH4)3ScF6; sodium hydroxide solution is added to the obtained (NH4)3ScF6, and the mixture is heated and stirred to obtain a sodium salt mixture; the sodium salt mixture is washed and dried to obtain Na3ScF6. This invention utilizes Sc2O3 and NH4HF2 as raw materials to obtain (NH4)3ScF6 containing both Sc and F elements through a fluorination reaction at low temperature and under simple operation. Specifically, plasma ball milling is used to achieve powder refinement and uniform dispersion, and inert gas plasma is used to activate the powder surface, promoting the chemical reaction and increasing the fluorination rate of scandium oxide. Secondly, this invention uses readily available NaOH as a raw material, utilizing the reaction of a strong base with a weak acid anion to promote the introduction of sodium ions, and excess NaOH can be removed by simple filtration. The preparation method of this invention is simple, convenient to operate, highly practical, easy to promote, and yields Na3ScF6 with high yield and high purity. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 The image shows the XRD pattern of Na3ScF6 obtained in Example 3 of this invention.

[0032] Figure 2This is a TEM image of Na3ScF6 obtained in Example 3 of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0034] Example 1

[0035] A Na3ScF6 and its preparation method, comprising the following steps:

[0036] S1. Place 50g Sc2O3 and 100g NH4HF2 into a ball mill jar protected by argon gas and ball mill. The mass of the steel ball is 2kg, the plasma discharge frequency is 8KHz, the rotation speed is 900rpm, and the ball milling time is 5min to obtain a prefluorinated compound (NH4). x ScF y Mixed powder;

[0037] S2. Place the mixed powder into a constant temperature heating magnetic stirrer and keep it at 60°C for 3 hours to obtain (NH4)3ScF6.

[0038] S3. The obtained (NH4)3ScF6 is mixed in a magnetic stirrer with constant temperature heating at a mass ratio of (NH4)3ScF6:NaOH solution (concentration of 50g / L) = 1:5, and kept at 60℃ for 8h to obtain a Na salt mixture.

[0039] S4. The Na salt mixture described in S3 is washed four times with pure water, and then filtered by a circulating water vacuum pump to obtain Na salt.

[0040] S5. Dry the Na salt described in S4 at 60°C for 2 hours to obtain Na3ScF6.

[0041] The yield of Na3ScF6 was verified to be 99.9%, and the purity was 99.99%.

[0042] Example 2

[0043] A Na3ScF6 and its preparation method, comprising the following steps:

[0044] S1. Place 50g Sc2O3 and 150g NH4HF2 into a ball mill jar under nitrogen protection and perform plasma ball milling. The mass of the steel ball is 2.5kg, the isostatic discharge frequency is 10KHz, the rotation speed is 1000rpm, and the ball milling time is 10min to obtain a prefluorinated compound (NH4). x ScF y Mixed powder;

[0045] S2. Place the mixed powder into a constant temperature heating magnetic stirrer and keep it at 70°C for 4 hours to obtain a specific (NH4)3ScF6.

[0046] S3. The obtained (NH4)3ScF6 is mixed in a magnetic stirrer with constant temperature heating at a mass ratio of (NH4)3ScF6:NaOH solution (concentration of 80g / L) = 1:7, and kept at 70℃ for 4h to obtain a Na salt mixture.

[0047] S4. The Na salt mixture described in S3 is washed multiple times with pure water, and then filtered by a circulating water vacuum pump to obtain Na salt.

[0048] S5. Dry the Na salt described in S4 at 100°C for 1.5 h to obtain Na3ScF6.

[0049] The yield of Na3ScF6 was verified to be 98%, and the purity was 99.5%.

[0050] Example 3

[0051] A Na3ScF6 and its preparation method, comprising the following steps:

[0052] S1. Place 50g Sc2O3 and 200g NH4HF2 into a ball mill jar protected by argon gas and perform plasma ball milling. The mass of the steel ball is 3kg, the isostatic discharge frequency is 12KHz, the rotation speed is 1200rpm, and the ball milling time is 5min to obtain a prefluorinated compound (NH4). x ScF y Mixed powder;

[0053] S2. Place the mixed powder into a constant temperature heating magnetic stirrer and keep it at 80°C for 4 hours to obtain a specific (NH4)3ScF6.

[0054] S3. The obtained (NH4)3ScF6 is mixed in a magnetic stirrer with constant temperature heating at a mass ratio of (NH4)3ScF6:NaOH solution (concentration of 100g / L) = 1:9, and kept at 80℃ for 4h to obtain a Na salt mixture.

[0055] S4. The Na salt mixture described in S3 is washed multiple times with pure water, and then filtered by a circulating water vacuum pump to obtain Na salt.

[0056] S5. Dry the Na salt described in S4 at 150°C for 1 hour to obtain Na3ScF6.

[0057] The yield of Na3ScF6 was verified to be 99.9%, and the purity was 99.99%.

[0058] Figure 1The image shows the XRD pattern of Na3ScF6 obtained in Example 3; Figure 2 This is a TEM image of Na3ScF6 obtained in Example 3. Figure 1 It can be seen that the obtained product only contains Na3ScF6; through Figure 2 It can be seen that the prepared Na3ScF6 exhibits a monoclinic columnar structure with a size of approximately 100-250 nm.

[0059] Comparative Example 1

[0060] A Na3ScF6 and its preparation method, comprising the following steps:

[0061] S1. Place 50g Sc2O3 and 100g NH4HF2 into a ball mill jar protected by argon gas and ball mill them. The mass of the steel balls is 2kg, the rotation speed is 900rpm, and the ball milling time is 5min to obtain a prefluorinated compound (NH4). x ScF y Mixed powder;

[0062] S2. Place the mixed powder into a constant temperature heating magnetic stirrer and keep it at 60°C for 3 hours to obtain (NH4)3ScF6.

[0063] S3. The obtained (NH4)3ScF6 is mixed in a magnetic stirrer with constant temperature heating at a mass ratio of (NH4)3ScF6:NaOH solution (concentration of 50g / L) = 1:5, and kept at 60℃ for 8h to obtain a Na salt mixture.

[0064] S4. The Na salt mixture described in S3 is washed four times with pure water, and then filtered by a circulating water vacuum pump to obtain Na salt.

[0065] S5. Dry the Na salt described in S4 at 60°C for 2 hours to obtain Na3ScF6.

[0066] The yield of Na3ScF6 was verified to be 90%, and the purity was 95%.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing Na3ScF6, characterized by, The method comprises the following steps: (1) Put scandium oxide and ammonium bifluoride into a ball mill tank protected by protective gas, and carry out plasma ball milling to obtain a mixed powder containing pre-fluoride (NH4) x ScF y ; (2) stirring the mixed powder at constant temperature to obtain (NH4)3ScF6; (3) adding sodium hydroxide solution into the obtained (NH4)3ScF6, and stirring under heating to obtain a sodium salt mixture; (4) washing and drying the sodium salt mixture to obtain Na3ScF6.

2. The production method according to claim 1, wherein The mass ratio of scandium oxide to ammonium bifluoride is 1:1.5-6.

3. The production method according to claim 1, wherein The ball-to-material mass ratio is 5-20:1, the plasma discharge frequency is 5-25 KHz, the rotating speed is 500-2000 rpm, and the ball milling time is 5-60 min.

4. The production method according to claim 1, wherein In step (2), the stirring is carried out at a temperature of 50-100 ℃ for 2-10 h.

5. The production method according to claim 4, wherein The constant temperature stirring is carried out by using a constant temperature heating magnetic stirrer.

6. The production method according to claim 5, wherein After adding the sodium hydroxide solution into (NH4)3ScF6, the molar ratio of sodium ions to fluoroscandate in the obtained solution is greater than or equal to 3.

7. The production method according to claim 1, wherein In step (3), the stirring is carried out at a frequency of 100-500 rpm and a temperature of 50-80 ℃ for 2-6 h.

8. The production method according to claim 1, wherein In step (4), the washing is carried out by using pure water to wash the sodium salt mixture.

9. The production method according to claim 1, wherein In step (4), the drying is carried out at a temperature of 50-150 ℃ for 1-2 h.

10. Na3ScF6 characterized in that, The method is prepared by using any one of the preparation methods in claims 1-9.

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