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CN-122010185-A - Synthesis method of rhenium hexafluoride

CN122010185ACN 122010185 ACN122010185 ACN 122010185ACN-122010185-A

Abstract

The application relates to the technical field of fluoride engineering, in particular to a synthesis method of rhenium hexafluoride. The method comprises the steps of S1, preheating fluorine-nitrogen mixed gas to 50-100 ℃ in a first temperature zone, S2, introducing the preheated fluorine-nitrogen mixed gas into a second temperature zone to react with rhenium metal to generate mixed gas containing rhenium hexafluoride, wherein the temperature of the second temperature zone is 120-180 ℃, S3, introducing the mixed gas containing rhenium hexafluoride into a third temperature zone to react with rhenium metal continuously, wherein the temperature of the third temperature zone is 300-450 ℃, S4, introducing the gas obtained by the reaction in S3 into a fourth temperature zone, controlling the temperature of the fourth temperature zone to be 200-300 ℃, and S5, collecting the gas generated in S4 at low temperature through a cold trap to obtain high-purity rhenium hexafluoride. The application reduces the impurity content and improves the purity of the product by controlling the temperature in a plurality of areas.

Inventors

  • PEI JIAYING
  • BO LIN
  • WANG YAFENG
  • LIU YUEXU
  • MIAO XIAOLI
  • LI XU
  • WANG YUE
  • KUANG JUN

Assignees

  • 中船(邯郸)派瑞特种气体股份有限公司

Dates

Publication Date
20260512
Application Date
20260228

Claims (10)

  1. 1. The synthesis method of rhenium hexafluoride is characterized by comprising the following steps: S1, preheating the fluorine-nitrogen mixed gas to 50-100 ℃ in a first temperature zone; s2, introducing the preheated fluorine-nitrogen mixed gas into a second temperature zone to react with rhenium metal to generate mixed gas containing rhenium hexafluoride, wherein the temperature of the second temperature zone is 120-180 ℃; s3, introducing mixed gas containing rhenium hexafluoride into a third temperature zone, and continuing to react with rhenium metal, wherein the temperature of the third temperature zone is 300-450 ℃; S4, introducing the gas obtained by the reaction in the step S3 into a fourth temperature zone, and controlling the temperature of the fourth temperature zone to be 200-300 ℃; and S5, collecting the gas generated in the step S4 through a cold trap at a low temperature to obtain the high-purity rhenium hexafluoride.
  2. 2. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the ratio of fluorine to nitrogen is 1 (0.5-2), and the flow rate of the fluorine-nitrogen mixture is 50-300 mL/min.
  3. 3. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the first, second, third and fourth temperature zones have a temperature rise rate of 5-50 ℃ per minute and a pressure of 0.05-0.20 mpa.
  4. 4. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the reaction time in the second temperature zone is 30-120 min, the molar ratio of fluorine gas to metal rhenium in the fluorine-nitrogen mixture is (3-6): 1, the gas residence time in the third temperature zone is 30-60 s, and the molar ratio of fluorine gas to metal rhenium in the fluorine-nitrogen mixture is 0.5:1.
  5. 5. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the reactor in the fourth temperature zone is filled with active carbon loaded with NiF 2 , the loading amount of NiF 2 is 10-15 wt%, and the gas residence time is 20-40 s.
  6. 6. The method of synthesizing rhenium hexafluoride as defined in claim 1, wherein said rhenium metal has a purity of 95% or greater.
  7. 7. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the temperature for low temperature collection is-80-10 ℃.
  8. 8. The method for synthesizing rhenium hexafluoride according to claim 1, wherein the materials of the reactors used in the steps S1 to S4 are any one of stainless steel, monel, and nickel-based alloys.
  9. 9. The method for synthesizing rhenium hexafluoride according to claim 1, characterized in that before the reaction starts, the reaction system is vacuumized to-0.1 Mpa, purged with nitrogen or inert gas to a pressure of 0.005-0.15 Mpa, and vacuumized and purged repeatedly for 10-20 times.
  10. 10. The method of synthesizing rhenium hexafluoride as claimed in claim 9, wherein the inert gas is helium or argon.

Description

Synthesis method of rhenium hexafluoride Technical Field The application relates to the technical field of fluoride engineering, in particular to a synthesis method of rhenium hexafluoride. Background Rhenium (Re) is a rare metal element of group VIIB of the sixth periodic table of elements, and has an atomic number of 75. It is a silvery heavy metal with extremely high melting and boiling points, and excellent high temperature strength, abrasion resistance and corrosion resistance. Has important effect in the advanced field of modern industry. Particularly in the aerospace field, rhenium-containing superalloys are widely used for manufacturing single crystal turbine blades and combustor components of high-performance aeroengines, and can improve the working temperature and thrust-weight ratio of the engines. In addition, rhenium is also used as a catalyst in the petrochemical industry for the manufacture of mass spectrometer filaments and high stability electrical contact materials in the electronics industry. Rhenium is extremely rare in the crust and is usually present as an accompanying element of minerals such as molybdenite, the extraction and purification processes of which are complex. Rhenium hexafluoride, as a fluoride of rhenium, is a pale yellow, volatile and chemically active liquid at ambient temperature. In the conventional preparation process of rhenium hexafluoride, fluorine is generally used as a fluorination reagent to directly react with the metallic rhenium. However, the fluorine gas has extremely strong corrosiveness and toxicity, so that the operation process is accompanied with high risk, strict requirements are put on production equipment, and further improvement of the purity of the product is difficult. Nitrogen trifluoride is a mild fluorinating agent, and has recently become a research hot spot in the field of fluoride synthesis. Compared with fluorine gas, nitrogen trifluoride has lower reactivity and better safety, however, how to realize the efficient fluorination of rhenium by nitrogen trifluoride is still a technical problem to be broken through. In addition, rhenium is easy to generate a byproduct rhenium heptafluoride in the fluorination reaction process, and the generation of the substance not only can reduce the purity of the target product rhenium hexafluoride, but also can have adverse effects on the separation and purification of subsequent products and the practical application. In the prior art, aiming at a system taking NF 3 as a fluorinating agent, a mature technical scheme capable of effectively inhibiting the generation of ReF 7 and converting the ReF 7 into ReF 6 is not formed. The technical document with publication number CN118320717A discloses a method for synthesizing rhenium hexafluoride crystal in a diamond anvil cell, wherein the diamond anvil cell is used as a reaction device, xenon difluoride is used as a fluorinating agent, liquid argon is used as a solvent to prepare rhenium hexafluoride, and the high-purity rhenium hexafluoride crystal is obtained by regulating and controlling the operating pressure. The method has the problems of high equipment cost, high experimental operation difficulty, small product sample amount and the like, and is difficult to realize large-scale mass production, meanwhile, the structure and the performance of the material can be unpredictably changed due to high-pressure operation, and strict safety protection measures are required to be equipped along with higher safety risks. Publication No. CN110589893B discloses a preparation method of rhenium hexafluoride, nitrogen trifluoride gas is introduced into a reactor filled with rhenium powder, fluorination reaction is carried out at the reaction temperature of 400-500 ℃ and the reaction pressure of 0.1-0.2 MPa, a condenser is adopted to collect and sublimate the generated rhenium hexafluoride and rhenium heptafluoride into mixed solid, and uncondensed nitrogen and nitrogen trifluoride gas in the product are discharged. Although the patent process aims to solve the problem of poor selectivity of the direct fluorination process by the reduction step, thus directionally producing rhenium hexafluoride, the rhenium hexafluoride product produced by this process has very limited purity. Therefore, development of a high-efficiency synthesis preparation method for rhenium hexafluoride, which has the advantages of controllable reaction conditions, simple process and easy industrial popularization, is needed to solve the problem of the current rhenium hexafluoride preparation. Disclosure of Invention Aiming at the problems of harsh reaction conditions, high product purification difficulty and the like in the prior art, the application provides a synthesis method of rhenium hexafluoride, which comprises the following steps: S1, preheating the fluorine-nitrogen mixed gas to 50-100 ℃ in a first temperature zone; s2, introducing the preheated fluorine-nitrogen mixed gas into a second tempe