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Method for fluorinating volatilizing recovery of uranium by using nitrogen trifluoride as fluorinating agent

A nitrogen trifluoride and uranium recovery technology, applied in chemical instruments and methods, plutonium halide, plutonium compounds, etc., can solve the problems of process equipment corrosion, poor safety, short service life, etc., and achieve low chemical toxicity and high safety. , the effect of long service life

Inactive Publication Date: 2019-09-03
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

[0007] The technical problem to be solved by the present invention is to overcome the defects of severe corrosion to process equipment, short service life and poor safety caused by using fluorine gas as a fluorinating agent in the fluorination volatilization process in the prior art, and provides a Method for recovering uranium by fluorinating and volatilizing nitrogen trifluoride as fluorinating agent

Method used

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  • Method for fluorinating volatilizing recovery of uranium by using nitrogen trifluoride as fluorinating agent
  • Method for fluorinating volatilizing recovery of uranium by using nitrogen trifluoride as fluorinating agent

Examples

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Embodiment 1

[0060] Example 1 Recovery of uranium in molten salt system of uranium-containing compound

[0061] (1) Will contain 3gUF 4 KF-ZrF 4 A total of 100g is placed in the reactor, the reactor lid is covered, and the atmosphere in the reactor is replaced with pure argon.

[0062] (2) Heat the reactor to increase the temperature from room temperature to 200°C, and then keep it for 2 hours; at the end of the temperature keeping, replace the atmosphere in the reactor with pure argon. The gas pipelines are heated to 100°C; a two-stage condenser is used, and the condenser temperature is -60°C. Continue to heat the reactor until the temperature reaches 700°C; keep it for 3h until the molten salt is completely melted, and pass a mixed gas of nitrogen trifluoride and argon (NF) into the molten fluoride salt in the reactor through a mass flow meter 3 The volume fraction is 50%), the flow rate is 0.2L / min, and the outlet gas of the reactor is detected by a Fourier infrared spectrometer.

[0063] (3)...

Embodiment 2 4

[0066] Example 2 Recovery of uranium in uranium tetrafluoride

[0067] (1) Put 50g UF 4 Place in the reactor, cover the reactor cover, and replace the atmosphere in the reactor with pure argon.

[0068] (2) Heat the reactor to increase the temperature from room temperature to 250°C, then keep it for 3 hours; at the end of the temperature keeping, replace the atmosphere in the reactor with pure argon. The gas pipelines are all heated to 100°C; the product is recovered by a two-stage adsorber with sodium fluoride as the adsorbent, and the temperature of the adsorber is 100°C. Continue to heat the reactor until the temperature reaches 500℃; keep it for 2h, and pass the mixed gas of nitrogen trifluoride and argon (NF 3 The volume fraction is 5%), the flow rate is 1L / min, and the outlet gas of the reactor is detected by a Fourier infrared spectrometer.

[0069] (3) UF in the reactor outlet gas after 2h 6 When the concentration is lower than the lower limit of infrared detection, stop fee...

Embodiment 3

[0072] Example 3 Recovery of uranium in molten salt system of uranium-containing compounds

[0073] (1) Will contain 20gUF 4 NaF-ZrF 4 A total of 1000 g is placed in the reactor, the reactor lid is covered, and the atmosphere in the reactor is replaced with pure argon.

[0074] (2) Heat the reactor to increase the temperature from room temperature to 250℃, then keep it for 3h; at the end of the heat preservation, replace the atmosphere in the reactor with pure argon; the gas pipelines are heated to 100℃; adopt two-stage condensation, the condenser temperature They are -40°C and -70°C respectively. Continue to heat the reactor until the temperature reaches 750°C; keep for 24 hours until the molten salt is completely melted, and pass a mixed gas of nitrogen trifluoride and argon (NF) into the molten fluoride salt in the reactor through a mass flow meter 3 The volume fraction is 10%), the flow rate is 2L / min, and Fourier infrared spectrometer is used to detect the outlet gas of the re...

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Abstract

The invention provides a method for fluorinating volatilizing recovery of uranium by using nitrogen trifluoride as a fluorinating agent. The method comprises: (1) removing air and water in a reactor,wherein the reactor is filled with the molten salt of a uranium-containing compound, or with a mixture containing elemental uranium, or with one or a plurality of uranium compounds, the uranium content in the molten salt of the uranium-containing compound is 0.01-30%, and the mixture containing elemental uranium is a mixture comprising elemental uranium and a nuclear fission product and / or a metalalloy; and (2) heating the reactor in stages, introducing a mixed gas of nitrogen trifluoride and an inert gas, carrying out a reaction, and recovering the reaction product, wherein the volume fraction of the nitrogen trifluoride in the mixed gas is 5-50%, heating is performed from a room temperature to 200-250 DEG C and first thermal insulation is performed in the first stage, and in the secondstage, heating is performed from the ending temperature of the first stage to 500-750 DEG C, and second thermal insulation is performed. According to the present invention, with the method, the safe,stable and long-term operation of the equipment can be achieved.

Description

Technical field [0001] The invention relates to a method for fluorinating and volatilizing nitrogen trifluoride as a fluorinating agent to recover uranium. Background technique [0002] Water is not used as a solvent in the dry reprocessing of spent fuel, and its main separation step is carried out at high temperatures. In addition, the process of dry post-processing of spent fuel has the advantages of radiation resistance, low criticality risk, and less radioactive waste, and is suitable for processing spent fuel with high burn-up and short cooling period. The fluorination volatilization technology is an important dry post-processing technology. The low-valent uranium is fluorinated into the high-valent fluoride UF through the following reaction 6 : [0003] UF 4 (d)+F 2 (g)→UF 6 (g) [0004] Utilize UF 6 The low boiling point and volatile of uranium can realize the separation and recovery of uranium. It is often used in natural uranium conversion, purification and enrichment of u...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G56/00
CPCC01G56/006
Inventor 孙理鑫牛永生胡聪伟窦强李晴暖
Owner SHANGHAI INST OF APPLIED PHYSICS - CHINESE ACAD OF SCI
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