Method for preparing potassium fluohafnate

Abstract

The embodiment of the invention discloses a method for preparing potassium fluohafnate. The method comprises the following steps: S1, reacting hafnium tetrachloride with a fluorine source to obtain hafnium tetrafluoride; the fluorine source is potassium fluoride; and S2, reacting hafnium tetrafluoride with potassium fluoride to obtain potassium hafnium fluoride. According to the method disclosed by the embodiment of the invention, efficient synthesis of K2HfF6 is realized by optimizing reaction conditions and paths, the process flow is simple, the process conditions are easy to control, the product purity is high, no harmful gas escapes, and the method is suitable for industrial amplification and has a good application prospect in the field of industrial preparation of potassium fluohafnate.

Description

Technical Field

[0001] This invention belongs to the field of inorganic chemistry technology, specifically relating to a method for preparing potassium fluorohafnium. Background Technology

[0002] Potassium fluorohafnium (K₂HfF₆) is an important hafnium compound widely used in nuclear reactor materials, catalysts, and the manufacture of specialty glasses. Due to the chemical similarities between hafnium and zirconium, traditional preparation methods often involve complex separation processes, such as solvent extraction or distillation. These methods are lengthy, costly, and may produce harmful byproducts. For example, the direct reaction of HfO₂ with potassium fluorosilicate requires high temperature and pressure conditions, and the byproducts are difficult to handle. Therefore, developing a simple, efficient, and environmentally friendly process for preparing K₂HfF₆ has significant industrial value. Summary of the Invention

[0003] In view of this, some embodiments disclose a method for preparing potassium fluorohafnium, comprising the steps of:

[0004] S1. Hafnium tetrachloride reacts with a fluorine source to yield hafnium tetrafluoride; the fluorine source is potassium fluoride.

[0005] S2, hafnium tetrafluoride reacts with potassium fluoride to give potassium fluorohafnium.

[0006] Furthermore, in some of the methods for preparing potassium fluorohafnium disclosed in the embodiments, the halogen exchange reaction is carried out in a potassium fluoride solvent.

[0007] Some embodiments disclose methods for preparing potassium fluorohafnium, wherein the molar ratio of hafnium tetrachloride to fluorine source is 1:4~6.

[0008] Some embodiments disclose methods for preparing potassium fluorohafnium, in which hafnium tetrachloride reacts with a fluorine source at a temperature of 250-400°C.

[0009] Some embodiments disclose methods for preparing potassium fluorohafnium, wherein the molar ratio of hafnium tetrafluoride to potassium fluoride is 1:2~3.

[0010] Some embodiments disclose a method for preparing potassium fluorohafnium, in which hafnium tetrafluoride reacts with potassium fluoride in an aqueous solution at a reaction temperature of 25-50°C.

[0011] Some embodiments disclose a method for preparing potassium fluorohafnium, wherein step S1 includes:

[0012] Hafnium tetrachloride and potassium fluoride are mixed at a set molar ratio of 1:4~6 and heated to 250~400℃ in a sealed reaction vessel to carry out a halogen exchange reaction, producing hafnium tetrafluoride and potassium chloride;

[0013] The product is cooled and washed with water or ethanol to remove potassium chloride, yielding solid hafnium tetrafluoride.

[0014] Some embodiments disclose a method for preparing potassium fluorohafnium, wherein step S2 includes:

[0015] Hafnium tetrafluoride and potassium fluoride are mixed at a set molar ratio of 1:2~3 to prepare an aqueous solution, which is placed in a sealed tube and reacted in the aqueous solution at 25~50℃ to produce potassium fluorohafnium fluoride.

[0016] The product was washed with ethanol and dried under vacuum at 50-100°C to obtain white crystalline potassium fluorohafnium with a purity of over 99.9%.

[0017] Some embodiments disclose methods for preparing potassium fluorohafnium, in which hafnium tetrachloride reacts with a fluorine source at a temperature of 300-350°C.

[0018] Some embodiments disclose methods for preparing potassium fluorohafnium, wherein the molar ratio of hafnium tetrafluoride to potassium fluoride is 1:2.5~3.

[0019] The method for preparing potassium fluorohafnium fluoride disclosed in this invention utilizes the halogen exchange reaction between hafnium tetrachloride and potassium fluoride to obtain hafnium tetrafluoride, and further utilizes the reaction between hafnium tetrafluoride and potassium fluoride to obtain potassium fluorohafnium fluoride. The method disclosed in this invention achieves efficient synthesis of K2HfF6 by optimizing reaction conditions and pathways. The process is simple, the process conditions are easy to control, the product has high purity, and no harmful gases are emitted. It is suitable for industrial scale-up and has good application prospects in the industrial preparation of potassium fluorohafnium fluoride. Detailed Implementation

[0020] The term "embodiment" used herein, as an example, is not necessarily to be construed as superior to or better than other embodiments. Performance testing in these embodiments of the invention, unless otherwise specified, employs conventional testing methods in the art. It should be understood that the terminology used in these embodiments is merely for describing particular implementations and is not intended to limit the scope of the disclosure of these embodiments.

[0021] Unless otherwise stated, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of this invention pertain; other experimental methods and technical means not specifically noted in the embodiments of this invention refer to experimental methods and technical means commonly used by one of ordinary skill in the art.

[0022] The terms “basic” and “approximately” as used herein are used to describe small fluctuations. For example, they can mean less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data presented or expressed in range format herein are used for convenience and brevity only, and should therefore be interpreted flexibly to include not only the explicitly listed values ​​that define the range, but also all independent values ​​or subranges contained within that range. For example, a numerical range of “1–5%” should be interpreted to include not only the explicitly listed values ​​from 1% to 5%, but also the independent values ​​and subranges within the indicated range. Thus, this numerical range includes independent values ​​such as 2%, 3.5%, and 4%, and subranges such as 1%–3%, 2%–4%, and 3%–5%, etc. This principle also applies to ranges that list only one value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.

[0023] In this document, including in the claims, conjunctions such as "comprising," "including," "with," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "consisting of" and "composed of" are closed conjunctions.

[0024] To better illustrate the content of this invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the invention can be practiced even without certain specific details. In the embodiments, some methods, means, instruments, and devices well-known to those skilled in the art are not described in detail, in order to highlight the main points of the invention.

[0025] Without conflict, the technical features disclosed in the embodiments of the present invention can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of the present invention.

[0026] In some embodiments, the method for preparing potassium fluorohafnium includes the steps of:

[0027] S1. Hafnium tetrachloride reacts with a fluorine source to yield hafnium tetrafluoride; the fluorine source is potassium fluoride. Typically, hafnium tetrachloride (HfCl4) and potassium fluoride (KF) are mixed in a predetermined molar ratio, placed in a sealed container, and subjected to a halogen exchange reaction under predetermined conditions to produce hafnium tetrafluoride (HfF4) and potassium chloride (KCl). After the reaction is complete, the product is cooled, and the potassium chloride (KCl) is washed away with a solvent to obtain solid hafnium tetrafluoride (HfF4).

[0028] The reaction formula is:

[0029] HfCl4 + 4KF → HfF4 + 4KCl;

[0030] Generally, the molar ratio of hafnium tetrachloride to potassium fluoride is set to 1:4~6, and the reaction temperature is set to 250~400℃.

[0031] In some embodiments, step S1 includes: mixing hafnium tetrachloride and potassium fluoride at a set molar ratio of 1:4~6, heating to 250~400°C in a sealed reaction vessel to carry out a halogen exchange reaction, generating hafnium tetrafluoride and potassium chloride; cooling the product, washing with water or ethanol to remove potassium chloride, and obtaining solid hafnium tetrafluoride.

[0032] As a preferred embodiment, the reaction temperature of hafnium tetrachloride with the fluorine source is 300~350°C to optimize the reaction rate and product purity.

[0033] S2. Hafnium tetrafluoride reacts with potassium fluoride to yield potassium fluorohafnate. Generally, the molar ratio of hafnium tetrafluoride to potassium fluoride is set to 1:2~3. The reaction of hafnium tetrafluoride and potassium fluoride is carried out in an aqueous solution at a temperature of 25~50℃.

[0034] The reaction is: HfF4 + 2KF → K2HfF6.

[0035] Typically, the reaction of hafnium tetrafluoride with potassium fluoride is carried out in a closed reaction vessel to prevent fluorine loss.

[0036] In some embodiments, step S2 includes: mixing hafnium tetrafluoride and potassium fluoride at a set molar ratio of 1:2~3 to prepare an aqueous solution, placing it in a sealed tube, and reacting it in the aqueous solution at 25~50°C to generate potassium fluorohafnium; washing the product with ethanol and drying it under vacuum at 50~100°C to obtain white crystalline potassium fluorohafnium with a purity of over 99.9%.

[0037] In a preferred embodiment, the molar ratio of hafnium tetrafluoride to potassium fluoride is 1:2.5~3; when HfF4 reacts with KF, the amount of KF is slightly in excess, and the molar ratio of KF to HfF4 is not less than 2.5:1 to ensure complete reaction.

[0038] The technical details are further illustrated below with reference to the embodiments.

[0039] Example 1

[0040] In this Example 1, the method for preparing potassium fluorohafnium acid includes:

[0041] HfCl4 and KF were mixed in a molar ratio of 1:4 and heated to 300°C in a sealed container for a halogen exchange reaction for 2 hours to produce HfF4 and KCl; after cooling, the mixture was washed with water to obtain solid HfF4.

[0042] The obtained HfF4 was mixed with KF at a molar ratio of 1:2 and reacted in an aqueous solution at 25°C for 2 hours to produce the product K2HfF6. The product was washed with ethanol and dried under vacuum to obtain K2HfF6 with a purity of 99.95%.

[0043] Example 2

[0044] The preparation method disclosed in Example 2 is the same as that in Example 1; wherein, the temperature of the halogen exchange reaction is set to 320°C, and the molar ratio of HfCl4 to KF is 1:5.

[0045] The purity of K2HfF6 obtained in Example 2 is 99.92%.

[0046] Example 3

[0047] The preparation method disclosed in Example 3 is the same as that in Example 1; wherein the reaction temperature of HfF4 and KF is set to 30°C.

[0048] The purity of K2HfF6 obtained in Example 3 is 99.98%.

[0049] Example 4

[0050] The preparation method disclosed in Example 4 is the same as that in Example 1; wherein, the temperature of the halogen exchange reaction is set to 400℃, and the molar ratio of HfCl4 to KF is 1:5.

[0051] The purity of K2HfF6 obtained in this embodiment is 99.93%.

[0052] Comparing Examples 1-4, it can be seen that the halogen exchange reaction temperature is 300℃, the reaction temperature of KF and HfF4 is 30℃, and the purity of the reaction product is relatively high.

[0053] The method for preparing potassium fluorohafnium fluoride disclosed in this invention utilizes the halogen exchange reaction between hafnium tetrachloride and potassium fluoride to obtain hafnium tetrafluoride, and further utilizes the reaction between hafnium tetrafluoride and potassium fluoride to obtain potassium fluorohafnium fluoride. The method disclosed in this invention achieves efficient synthesis of K2HfF6 by optimizing reaction conditions and pathways. The process is simple, the process conditions are easy to control, the product has high purity, and no harmful gases are emitted. It is suitable for industrial scale-up and has good application prospects in the industrial preparation of potassium fluorohafnium fluoride.

[0054] The technical solutions and technical details disclosed in the embodiments of this invention are merely illustrative of the inventive concept of this invention and do not constitute a limitation on the technical solutions of the embodiments of this invention. Any conventional changes, substitutions, or combinations made to the technical details disclosed in the embodiments of this invention have the same inventive concept as this invention and are within the protection scope of the claims of this invention.

Claims

1. A method for preparing potassium fluorohafnium phosphate, characterized in that, Including the following steps: S1. Hafnium tetrachloride reacts with a fluorine source to yield hafnium tetrafluoride; the fluorine source is potassium fluoride. S2, hafnium tetrafluoride reacts with potassium fluoride to give potassium fluorohafnium.

2. The method for preparing potassium fluorohafnium phosphate according to claim 1, characterized in that, The halogen exchange reaction is carried out in potassium fluoride solvent.

3. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, The molar ratio of hafnium tetrachloride to the fluorine source is 1:4~6.

4. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, The reaction temperature between hafnium tetrachloride and the fluorine source is 250~400℃.

5. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, The molar ratio of hafnium tetrafluoride to potassium fluoride is 1:2~3.

6. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, The hafnium tetrafluoride reacts with the potassium fluoride in an aqueous solution at a temperature of 25-50°C.

7. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, Step S1 includes: Hafnium tetrachloride and potassium fluoride are mixed at a set molar ratio of 1:4~6 and heated to 250~400℃ in a sealed reaction vessel to carry out a halogen exchange reaction, producing hafnium tetrafluoride and potassium chloride; The product is cooled and washed with water or ethanol to remove potassium chloride, yielding solid hafnium tetrafluoride.

8. The method for preparing potassium fluorohafnium fluoride according to claim 1, characterized in that, Step S2 includes: Hafnium tetrafluoride and potassium fluoride are mixed at a set molar ratio of 1:2~3 to prepare an aqueous solution, which is placed in a sealed tube and reacted in the aqueous solution at 25~50℃ to produce potassium fluorohafnium fluoride. The product was washed with ethanol and dried under vacuum at 50-100°C to obtain white crystalline potassium fluorohafnium with a purity of over 99.9%.

9. The method for preparing potassium fluorohafnium phosphate according to claim 7, characterized in that, The reaction temperature between hafnium tetrachloride and the fluorine source is 300~350℃.

10. The method for preparing potassium fluorohafnium fluoride according to claim 8, characterized in that, The molar ratio of hafnium tetrafluoride to potassium fluoride is 1:2.5~3.