Ytterbium fluoride particles and preparation method thereof

Abstract

The invention provides ytterbium fluoride particles and a preparation method thereof. The preparation method of the ytterbium fluoride particles comprises the following steps: S1, in an inert atmosphere, heating ytterbium fluoride powder to obtain molten ytterbium fluoride; the heating temperature ranges from 1170 DEG C to 1600 DEG C, and the pressure of the inert atmosphere ranges from 200 pa to 300 pa; s2, mixing the molten ytterbium fluoride with a fluorine nitrogen compound, and then cooling under a vacuum condition to obtain ytterbium fluoride particles; the temperature of the mixing treatment is 1170 to 1600 DEG C. According to the technology, the single-phase polycrystalline ytterbium fluoride particles can be prepared, the purity of the single-phase polycrystalline ytterbium fluoride particles is 99.99% or above, and the ytterbium fluoride particles do not contain OH impure phases and have high yield.

Description

Technical Field

[0001] The present invention relates to ytterbium fluoride particles and a preparation method thereof. Background Art

[0002] In recent years, the demand for fluoride vapor-deposited materials in fields such as optical fiber communications and medicine has been growing year by year. Vapor-depositing a certain amount of ytterbium fluoride on optical devices can make fluoride glass have excellent near-infrared and special optical properties.

[0003] When preparing ytterbium fluoride polycrystalline ingots, existing technology uses ytterbium fluoride powder as the raw material. This ytterbium fluoride powder contains some incompletely fluorinated ytterbium oxide. Furthermore, ytterbium fluoride powder is highly hygroscopic, absorbing moisture from the air. This impurity, ytterbium oxide, and moisture react with each other during the pelletizing and casting process to form ytterbium oxide hydroxide, resulting in the appearance of an OH impurity during phase analysis, significantly impacting subsequent coating applications.

[0004] Therefore, there is an urgent need for a method for preparing ytterbium fluoride particles so that the ytterbium fluoride particles do not contain OH impurity phase. Summary of the Invention

[0005] To address the difficulties of obtaining polycrystalline ytterbium fluoride using existing preparation methods, which often result in the presence of an OH impurity, the present invention provides ytterbium fluoride particles and a method for preparing the same. The process of the present invention produces single-phase polycrystalline ytterbium fluoride particles with a purity exceeding 99.99%, free of OH impurities, and a high yield, specifically 80% or higher.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a method for preparing ytterbium fluoride particles, which comprises the following steps:

[0008] S1. Heating ytterbium fluoride powder under an inert atmosphere to obtain molten ytterbium fluoride; the heating temperature is 1170-1600° C., and the pressure of the inert atmosphere is 200-300 Pa;

[0009] S2. Mixing the molten ytterbium fluoride with a fluorine-nitrogen compound, and then cooling under vacuum conditions to obtain ytterbium fluoride particles; the mixing temperature is 1170-1600° C.

[0010] In the present invention, ytterbium fluoride is prepared from powder into large particles through the design of process conditions. However, during the preparation process, the ytterbium fluoride powder often contains some incompletely fluorinated ytterbium oxide. Ytterbium fluoride powder has strong hygroscopicity and absorbs water vapor from the air. At room temperature, ytterbium fluoride and ytterbium oxide react weakly with water. However, during the melting and casting process, as the temperature rises, both the ytterbium fluoride and the impurity ytterbium oxide undergo a vigorous hydrolysis reaction with water vapor, forming ytterbium oxide hydroxide. Therefore, using conventional methods in the art, the ytterbium fluoride produced often contains an OH impurity phase, which affects the morphology of the ytterbium fluoride.

[0011] In the present invention, the pressure of the inert atmosphere refers to the absolute pressure of the system containing inert gas.

[0012] In some embodiments, in step S1, the purity of the ytterbium fluoride powder is 99% or higher, preferably 99.99% or higher; and in the ytterbium fluoride powder, except for ytterbium fluoride, the content of other impurities is less than 0.01%.

[0013] In some embodiments, in step S1, the particle size of the ytterbium fluoride powder is in the range of 0.05-60 μm.

[0014] In a specific embodiment, the D50 particle size of the ytterbium fluoride powder is 0.25-1 μm, for example, 0.397 μm.

[0015] In step S1 of the present invention, the ytterbium fluoride powder is generally prepared by reacting ytterbium oxide with hydrogen fluoride; however, this existing preparation method cannot achieve a 100% fluorination rate, and some incompletely reacted ytterbium oxide will exist in the ytterbium fluoride powder.

[0016] In some embodiments, in step S1, the inert atmosphere includes nitrogen, argon, or helium; during the process of heating and melting the ytterbium fluoride powder, the inert atmosphere can suppress the volatilization of ytterbium fluoride, thereby facilitating the formation of single-phase polycrystalline ytterbium fluoride.

[0017] In step S1 of the present invention, the pressure of the inert atmosphere needs to be in the range of 200-300 Pa. If the pressure is 500 Pa, the ammonium fluoride added in step S2 will not be completely volatilized, resulting in excessive nitrogen content in the product.

[0018] In some embodiments, in step S1, the pressure of the inert atmosphere is 200-280 Pa, for example, 220 Pa.

[0019] In some embodiments, in step S1, the heating process is performed in a vacuum melting furnace; before the heating process, ytterbium fluoride powder needs to be added into the vacuum melting furnace in advance.

[0020] Wherein, the vacuum melting furnace may be provided with an observation window for observing the state of the material in the furnace.

[0021] In some embodiments, in step S1, the heating temperature is 1200-1600°C.

[0022] In a specific embodiment, the heating process comprises the following steps:

[0023] s1. Open the exhaust valve, heat the vacuum melting furnace to 350-700°C within 30-60 minutes, and then maintain the temperature for 6-8 hours; both the heating and the temperature maintenance are performed at a pressure of 0-10 Pa.

[0024] s2. Close the exhaust valve and introduce inert gas into the vacuum melting furnace to form the inert atmosphere.

[0025] In step s1, when the pressures of the heating and constant temperature treatments are both 0-10 Pa, it can be ensured that the system is in an anhydrous state.

[0026] In one embodiment, in step s1, the vacuum melting furnace is heated to 400° C. within 40 minutes and then maintained at a constant temperature for 6 hours, during which the pressure is maintained at 2 Pa.

[0027] In some embodiments, the fluorine-nitrogen compound is added when all of the ytterbium fluoride powder is in a molten state.

[0028] In the present invention, by adding fluorine-nitrogen compounds to the molten ytterbium fluoride, it is possible to prevent the ytterbium fluoride or the impurity ytterbium oxide from being hydrolyzed to form an OH impurity phase during the heating process.

[0029] In some embodiments, in step S2, the amount of the fluorine-nitrogen compound added is 1%-5%, where % refers to the ratio of the mass of the fluorine-nitrogen compound to the mass of the molten ytterbium fluoride.

[0030] In some embodiments, in step S2, the fluorine nitrogen compound includes ammonium fluoride.

[0031] Among them, the use of ammonium fluoride can prevent ytterbium fluoride or impurity ytterbium oxide from hydrolyzing to form OH impurity phase during the heating process; and even if OH impurity phase already exists in ytterbium fluoride, the impurity phase can react with ammonium fluoride according to the following reaction equation: Yb(OH)3+ 3NH4F = YbF3+ 3NH3+ 3H2O.

[0032] In some embodiments, in step S2, the mixing treatment time is 5-10 min.

[0033] In some embodiments, in step S2, the temperature of the mixing treatment is 1200-1600°C.

[0034] In the present invention, after the mixing process, preferably, the molten material is cast onto a mold under vacuum and allowed to cool naturally; after cooling to the target temperature, the ytterbium fluoride particles are taken out of the mold, vacuum-packaged, and stored in a drying oven.

[0035] The present invention also provides ytterbium fluoride particles, which are prepared using the above-mentioned method for preparing ytterbium fluoride particles.

[0036] In some embodiments, the ytterbium fluoride particles have a single-phase polycrystalline structure.

[0037] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0038] The reagents and raw materials used in the present invention are commercially available.

[0039] The positive progress effect of the present invention is:

[0040] The process of the present invention can produce single-phase polycrystalline ytterbium fluoride particles with a purity of more than 99.99%. The ytterbium fluoride particles do not contain OH impurity phases and have a high yield, specifically 80% or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a particle size distribution diagram of the raw material ytterbium fluoride powder of the embodiment of the present application;

[0042] Figure 2 The XRD pattern of the ytterbium fluoride particles obtained in Example 1 of the present application;

[0043] Figure 3 The XRD diffraction patterns of the ytterbium fluoride particles obtained in Example 1 and Comparative Example 1 of the present application are shown;

[0044] Figure 4 This is a scanning electron microscope image of the ytterbium fluoride particles produced in Example 1 of the present application. DETAILED DESCRIPTION

[0045] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0046] The raw material ytterbium fluoride powder is selected from ytterbium fluoride with a purity of 99.99% produced by Fujian Jinlong Rare Earth Co., Ltd., and is tested by GDMS (glow discharge mass spectrometry) using a laser scattering particle size distribution analyzer (HORIBA, LA-960). The purity of the ytterbium fluoride in the raw material ytterbium fluoride powder used in the examples of the present application is 99.99% or higher, and the content of other impurities is less than 0.01%.

[0047] Figure 1 This is a particle size distribution diagram of the raw material ytterbium fluoride powder of the examples of this application. Among them, the transmittance (Laser) of the ytterbium fluoride powder is 92.3%, and the transmittance (Lamp) is 80.8%; the particle size range of the ytterbium fluoride powder is 0.05~60μm; among them, the particle sizes of D0, D10, D25, D50, D75, D90, D95, D100, and D99 of the ytterbium fluoride powder are 0.0581 μm, 0.1656 μm, 0.2399 μm, 0.3970 μm, 1.2530 μm, 5.8171 μm, 19.4274 μm, 58.9463 μm, and 36.4099 μm, respectively; the average diameter is 2.74085 μm, the arithmetic standard deviation is 7.0473 μm, the geometric mean diameter is 0.6461 μm, and the geometric standard deviation is 4.1549 μm, and the frequency diameter is 0.2771 μm.

[0048] The ytterbium fluoride powder used in the following examples and comparative examples is obtained by reacting ytterbium oxide with hydrogen fluoride. However, since this reaction generates water, which is easily absorbed by the generated ytterbium fluoride, there will be a small amount of water in the raw material ytterbium fluoride powder. Therefore, if the conventional method in the field is used to prepare ytterbium fluoride particles, OH impurity phase will be generated therein.

[0049] Example 1

[0050] This embodiment provides an ytterbium fluoride particle and a preparation method thereof; the preparation method comprises the following steps:

[0051] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0052] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0053] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 220 Pa;

[0054] Step 4: Raise the temperature of the vacuum melting furnace to 1200°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0055] Step 5: Add 50 g of ammonium fluoride to the molten ytterbium fluoride from the feeding port of the vacuum melting furnace and mix for 5 minutes. During the mixing process, the temperature is kept the same as that in step 4.

[0056] Step 6: Turn off the heating, and under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold, and allow it to cool naturally;

[0057] Step 7: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven to obtain ytterbium fluoride particles.

[0058] The ytterbium fluoride particles prepared in this example were analyzed by XRD using a YbF 3 standard sample. The testing instrument used was manufactured by PANalytical of the Netherlands and its model number was X'pert Pro. Figure 2 is the XRD pattern of the ytterbium fluoride particles of the product of Example 1; Figure 2 XRD analysis shows that the ytterbium fluoride particles obtained in Example 1 are single-phase.

[0059] The yield of ytterbium fluoride particles prepared in this example is 80%, which is calculated as follows:

[0060] The weight of ytterbium fluoride particles of qualified size produced / the weight of ytterbium fluoride powder input = 800g / 1000g * 100% = 80%.

[0061] Comparative Example 1

[0062] This comparative example provides an ytterbium fluoride particle and a preparation method thereof. In the preparation method of this comparative example, no fluorine-nitrogen compound is added, and other conditions are similar to those of the embodiment. Specifically, the preparation method comprises the following steps:

[0063] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0064] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0065] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 220 Pa;

[0066] Step 4: Raise the temperature of the vacuum melting furnace to 1200°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0067] Step 5: Turn off the heating and, under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold and allow it to cool naturally;

[0068] Step 6: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven to obtain ytterbium fluoride particles.

[0069] The XRD pattern of the ytterbium fluoride particles obtained in this comparative example was analyzed by the XRD method in Example 1, and compared with the XRD pattern of the ytterbium fluoride particles obtained in Example 1; Figure 3 The XRD diffraction patterns of the ytterbium fluoride particles of Example 1 and Comparative Example 1 are shown; Figure 3 Comparing the XRD diffraction peaks of the ytterbium fluoride particles in Example 1 and Comparative Example 1, the ytterbium fluoride particles prepared in Example 1 do not contain OH impurity phase.

[0070] Since no fluorine and nitrogen compounds are added during the smelting process, ytterbium fluoride or impurity ytterbium oxide hydrolyzes during the heating process; the resulting product ytterbium fluoride particles contain OH impurity phase.

[0071] Comparative Example 2

[0072] This comparative example provides ytterbium fluoride particles and a preparation method thereof. In the preparation method of this comparative example, the pressure of the vacuum melting furnace is too low, and other conditions are similar to those in the embodiment. Specifically, the preparation method comprises the following steps:

[0073] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0074] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0075] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 50 Pa;

[0076] Step 4: Raise the temperature of the vacuum melting furnace to 1200°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0077] Step 5: Add 50g of ammonium fluoride to the molten ytterbium fluoride from the feeding port of the vacuum melting furnace and mix for 5 minutes;

[0078] Step 6: Turn off the heating, and under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold, and allow it to cool naturally;

[0079] Step 7: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven to obtain ytterbium fluoride particles.

[0080] XRD analysis revealed that the ytterbium fluoride particles produced in this comparative example contained an OH phase. Due to the low pressure, the added ammonium fluoride volatilized before reacting with the OH phase, increasing the volatilization of ytterbium fluoride. Consequently, the product obtained in this comparative example contained an OH phase. The yield of this comparative example product was 65%, calculated as follows: weight of ytterbium fluoride particles of acceptable size produced / weight of ytterbium fluoride powder input = 650g / 1000g * 100% = 65%.

[0081] Comparative Example 3

[0082] This comparative example provides ytterbium fluoride particles and a preparation method thereof. In the preparation method of this comparative example, the pressure of the vacuum melting furnace is too high, and other conditions are similar to those in the embodiment. Specifically, the preparation method comprises the following steps:

[0083] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0084] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0085] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 500 Pa;

[0086] Step 4: Raise the temperature of the vacuum melting furnace to 1200°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0087] Step 5: Add 50g of ammonium fluoride to the molten ytterbium fluoride from the feeding port of the vacuum melting furnace and mix for 5 minutes;

[0088] Step 6: Turn off the heating, and under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold, and allow it to cool naturally;

[0089] Step 7: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven to obtain ytterbium fluoride particles.

[0090] Due to the high pressure, the volatilization of ammonium fluoride is suppressed. Therefore, the oxygen and nitrogen analyzer model ON-3000 produced by Gangyan Nake Testing Technology Co., Ltd. is used to analyze the product obtained in this comparative example. The N content exceeds the standard, the N content increases, and the product structural strength decreases; and the product yield of this comparative example is 70%.

[0091] Comparative Example 4

[0092] This comparative example provides ytterbium fluoride particles and a preparation method thereof. In the preparation method of this comparative example, the heating temperature is too low, and other conditions are similar to those in the embodiment. Specifically, the preparation method comprises the following steps:

[0093] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0094] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0095] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 220 Pa;

[0096] Step 4: Raise the temperature of the vacuum melting furnace to 1165°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0097] Step 5: Add 50g of ammonium fluoride to the molten ytterbium fluoride from the feeding port of the vacuum melting furnace and mix for 5 minutes;

[0098] Step 6: Turn off the heating, and under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold, and allow it to cool naturally;

[0099] Step 7: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven to obtain ytterbium fluoride particles.

[0100] Since the vacuum melting temperature was too low, the strength of the product after casting was low, and the number of formed ytterbium fluoride particles was small. The product yield of this comparative example was 45%.

[0101] Comparative Example 5

[0102] This comparative example provides ytterbium fluoride particles and a preparation method thereof. In the preparation method of this comparative example, the heating temperature is too high, and other conditions are similar to those of the embodiment. Specifically, the preparation method comprises the following steps:

[0103] Step 1: Add 1 kg of ytterbium fluoride into a crucible in a vacuum melting furnace;

[0104] Step 2: Open the exhaust valve and start the vacuum melting furnace to heat, raise the temperature to 400°C in 40 minutes, keep the temperature constant for 6 hours, and maintain the pressure at 2 Pa during this period;

[0105] Step 3: Close the exhaust valve and introduce inert gas into the smelting furnace until the pressure reaches 220 Pa;

[0106] Step 4: Raise the temperature of the vacuum melting furnace to 1700°C and observe from the observation port of the melting furnace until all the ytterbium fluoride in the crucible is in a molten state;

[0107] Step 5: Add 50g of ammonium fluoride to the molten ytterbium fluoride from the feeding port of the vacuum melting furnace and mix for 5 minutes;

[0108] Step 6: Turn off the heating, and under vacuum, cast the molten ytterbium fluoride in the crucible onto the mold, and allow it to cool naturally;

[0109] Step 7: After cooling to the target temperature, take out the ytterbium fluoride from the mold, vacuum-pack it and store it in a drying oven.

[0110] Since the vacuum melting temperature is too high, analysis using HORIBA's x-act energy spectrum analyzer shows that part of the YbF3 in the particles has been transformed into YbF2 and an impurity phase has appeared.

[0111] Effect Example 1

[0112] The morphology of the ytterbium fluoride particles of Example 1 was observed using a microscope model LM100 from Wright Corporation. Figure 4 This is a scanning electron microscope image of the ytterbium fluoride particles produced in Example 1 of the present application.

[0113] Microscopic observation of the product of Example 1 revealed that the product of Example 1 had multiple crystal planes and had a polycrystalline structure.

Claims

1. A method for preparing ytterbium fluoride particles, characterized in that: It includes the following steps: S1. In an inert atmosphere, heating ytterbium fluoride powder to obtain molten ytterbium fluoride; the heating temperature is 1170-1600° C., and the pressure of the inert atmosphere is 200-300 Pa; S2. Mixing the molten ytterbium fluoride with the fluorine-nitrogen compound, and then cooling under vacuum conditions to obtain ytterbium fluoride particles; the mixing temperature is 1170-1600°C.

2. The method for preparing ytterbium fluoride particles according to claim 1, characterized in that: In step S1, the ytterbium fluoride powder satisfies one or both of the following conditions: ① The purity of the ytterbium fluoride powder is 99% or above; ② The particle size of the ytterbium fluoride powder is in the range of 0.05-60 μm.

3. The method for preparing ytterbium fluoride particles according to claim 2, characterized in that: The ytterbium fluoride powder satisfies one or both of the following conditions: ① The purity of the ytterbium fluoride powder is 99.99% or above; ② The D50 particle size of the ytterbium fluoride powder is 0.25-1 μm.

4. The method for preparing ytterbium fluoride particles according to claim 1, characterized in that: Step S1 satisfies one or more of the following conditions: ① The inert atmosphere includes nitrogen, argon or helium; ② The pressure of the inert atmosphere is 200-280 pa; ③ The heating process is carried out in a vacuum melting furnace; ④The heating temperature is 1200-1600°C.

5. The method for preparing ytterbium fluoride particles according to claim 4, characterized in that: The heating process comprises the following steps: s1. Open the exhaust valve, raise the temperature of the vacuum melting furnace to 350-700°C within 30-60 minutes, and then treat it at a constant temperature for 6-8 hours; the heating and the constant temperature treatment are both carried out under a pressure of 0-10 Pa; s2. Close the exhaust valve and introduce inert gas into the vacuum melting furnace to form the inert atmosphere.

6. The method for preparing ytterbium fluoride particles according to claim 1, characterized in that: In step S2, the amount of the fluorine-nitrogen compound added is 1%-5%, where % refers to the ratio of the mass of the fluorine-nitrogen compound to the mass of the molten ytterbium fluoride.

7. The method for preparing ytterbium fluoride particles according to claim 1, characterized in that: In step S2, the fluorine nitrogen compound includes ammonium fluoride.

8. The method for preparing ytterbium fluoride particles according to claim 1, characterized in that: Step S2 satisfies one or both of the following conditions: ① The mixing time is 5-10 min; ② The temperature of the mixing treatment is 1200~1600℃.

9. An ytterbium fluoride particle, characterized in that: The ytterbium fluoride particles are prepared by the method for preparing the ytterbium fluoride particles as described in any one of claims 1 to 8.

10. The ytterbium fluoride particles according to claim 9, characterized in that The ytterbium fluoride particles have a single-phase polycrystalline structure.

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