A kind of molten salt deoxidation method using nitrogen trifluoride as fluorinating agent

A technology of nitrogen trifluoride and fluorinating agent, which is applied in chemical instruments and methods, fluoride preparation, alkali metal fluoride, etc., and can solve problems such as high cost, equipment corrosion, and poor process safety

Active Publication Date: 2020-10-23
SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects of poor safety of the existing process, serious equipment corrosion, complicated operation and high cost, and provide a molten salt deoxidation method using nitrogen trifluoride as the fluorinating agent

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Example 1KF-ZrF 4 Molten salt system deoxidation

[0041] (1) 2000gKF-ZrF 4 (58-42mol%) is placed in the reactor, the lid of the kettle is covered, and the atmosphere in the reactor is replaced with pure argon.

[0042](2) Heating the reactor to raise the temperature from room temperature to 200°C, and keep it warm for 3 hours; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon; heat the reactor again, and raise the temperature from 200°C to 350°C, keep it warm 3h; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon to remove the water generated during the heating process. Continue to heat the reactor to make the temperature reach 600°C; keep it warm for 3 hours until the molten salt is completely melted, and pass the mixed gas of nitrogen trifluoride and argon (NF 3 The volume fraction is 10%), and the flow rate is 1L / min to carry out purification and deoxidation.

[0043] (3) Stop feedi...

Embodiment 2

[0045] Example 2NaF-ZrF 4 Molten salt system deoxidation

[0046] (1) 1000g NaF-ZrF 4 (59.5-40.5mol%) is placed in the reactor, the lid of the kettle is covered, and the atmosphere in the reactor is replaced with pure argon.

[0047] (2) Heating the reactor to raise the temperature from room temperature to 250°C, and keep it warm for 2 hours; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon; heat the reactor again, and raise the temperature from 250°C to 400°C, then keep it warm 2h; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon to remove the water generated during the heating process. Continue to heat the reactor to make the temperature reach 700°C; keep it warm for 5 hours until the molten salt is completely melted, and pass the mixed gas of nitrogen trifluoride and argon (NF 3 The volume fraction is 20%), and the flow rate is 0.5L / min to carry out purification and deoxidation.

[0048]...

Embodiment 3

[0050] Example 3LiF-BeF 2 Molten salt system deoxidation

[0051] (1) 5kg LiF-BeF 2 (67-33mol%) is placed in the reactor, the lid of the kettle is covered, and the atmosphere in the reactor is replaced with pure argon.

[0052] (2) Heating the reactor to raise the temperature from room temperature to 200°C, and keep it warm for 2 hours; replace the atmosphere in the reactor with pure argon at the end of the heat preservation; heat the reactor again, and raise the temperature from 200°C to 400°C, keep it warm 2h; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon to remove the water generated during the heating process. Continue to heat the reactor to make the temperature reach 500°C; keep warm for 10 hours until the molten salt is completely melted, and feed a mixed gas of nitrogen trifluoride and argon into the molten fluoride salt in the reactor through a mass flow meter (the volume fraction of NF3 is 50%), the flow rate is 2L / min, ...

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PUM

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Abstract

The invention discloses a molten salt deoxidizing method using nitrogen trifluoride as a fluorinating agent. The molten salt deoxidizing method comprises the following steps: (1) removing air and water in a reactor, wherein the reactor is filled with a molten salt; (2) heating the reactor until the molten salt is completely melted, introducing a mixed gas of nitrogen trifluoride and an inert gas,and performing a reaction for 12-72 h, wherein the volume fraction of the nitrogen trifluoride in the mixed gas of nitrogen trifluoride and the inert gas is 5-50%. The method using the nitrogen trifluoride instead of hydrogen fluoride as the fluorinating agent overcomes the defects of poor safety, severe corrosion and short service life of a the reactor, complexity in operation and high cost in the prior art; and the nitrogen trifluoride has a low chemical toxicity, and has stable properties at room temperature.

Description

technical field [0001] The invention belongs to the field of nuclear energy industry technology and dry metallurgy technology, and specifically relates to a method for deoxidizing molten salt using nitrogen trifluoride as a fluorinating agent. Background technique [0002] The molten salt reactor is the only liquid fuel reactor among the fourth generation reactors, and its main feature is the use of molten fluorine salt as the nuclear fuel carrier salt and / or coolant. The pure molten salt system is less corrosive, but when the molten salt contains water and oxygen impurities, its corrosiveness to the reactor and loop piping increases. In addition, some oxides may react with nuclear fuel to generate slurry or precipitate in the reactor, resulting in unstable operation of the reactor and even accidents. Therefore, maintaining a low oxygen content in the molten salt system is of great significance for reducing corrosion and ensuring safe operation of the reactor. [0003] In ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B9/08C01D3/02C01G25/04C01D15/04C01F3/00G21C3/54
CPCC01B9/08C01D3/02C01D15/04C01F3/00C01G25/04C01P2002/89G21C3/54Y02E30/30
Inventor 牛永生胡聪伟孙理鑫窦强李晴暖
Owner SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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