Application of ammonium chloride for separating uranium dioxide and lanthanide oxide

A technology of lanthanide elements and uranium dioxide, which is applied in the application field of ammonium chloride in the separation of uranium dioxide and lanthanide oxides, can solve the problems of high melting and boiling point, long chlorination time, and difficult separation, and achieves The effect of mild reaction conditions, low equipment requirements and simple operation

Active Publication Date: 2018-08-03
INST OF HIGH ENERGY PHYSICS CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For metal chlorides, most of the chlorination effect is not good, the chlorination time is longer, and the corresponding oxides are formed and precipitated at the bottom of the molten salt, and it is difficult to separate these by-products from the molten salt
At high temperature, Cl 2 The chlorination and dissolution of uranium dioxide can be achieved by adding a reducing agent (C or CO), but the resulting product is UCl 4 , UCl 5 ,UCl 6 A mixture of which UCl 5 ,UCl 6 Severe volatilization, resulting in a large loss of U
CCl4 decomposes seriously under high temperature conditions, and also exists with Cl 2 Similar U loss problem
In addition, Cl 2 with CCl 4 It is highly corrosive under high temperature conditions, which requires extremely high equipment and expensive equipment
[0004] On the other hand, in oxide spent fuel, UO 2 with Ln x o y The separation of
Some researchers hope to remove volatile fragmentation products in oxidized spent fuel by oxidative volatilization, but due to the x o y High melting and boiling point, difficult to achieve effective separation

Method used

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  • Application of ammonium chloride for separating uranium dioxide and lanthanide oxide
  • Application of ammonium chloride for separating uranium dioxide and lanthanide oxide
  • Application of ammonium chloride for separating uranium dioxide and lanthanide oxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Example 1: UO 2 Dissolution Test in Chloride Molten Salt System

[0036] UO 2 For the dissolution process in the chloride molten salt system see figure 1 .

[0037](1) Mix 8.8g LiCl and 11.2g KCl evenly, place in an alumina crucible, place in a vacuum oven, dry at 150°C for more than 72 hours, and set aside.

[0038] (2) Add 0.14g UO 2 powder with 2g NH 4 The Cl powder was mixed evenly, and spread on top of the LiCl-KCl mixed salt at room temperature.

[0039] (3) Heat the high-temperature resistance furnace to 500°C, then place the corundum crucible containing the mixture in the resistance furnace, and keep a constant temperature of 500°C for reaction.

[0040] (4) After placing the corundum crucible in the resistance furnace, fasten the quartz condenser above the crucible to recover the rapidly volatilized NH 4 Cl, causing ammonium chloride to condense on the inner wall of the quartz tube.

[0041] (5) After keeping at 500°C for 5 hours, UO 2 All dissolved. A...

Embodiment 2

[0045] (1) Mix 44.8g LiCl and 55.2g KCl evenly, place in an alumina crucible, place in a vacuum oven, dry at 150°C for more than 72 hours, and set aside.

[0046] (2) 0.26g UO 2 powder with 4g NH 4 The Cl powder was mixed evenly, and spread on top of the LiCl-KCl mixed salt at room temperature.

[0047] (3) Heat the high-temperature resistance furnace to 500°C in an argon-protected glove box, the water and oxygen content of the glove box are less than 5ppm, then place the corundum crucible with the mixture in the resistance furnace, and keep it at a constant temperature of 500°C for reaction.

[0048] (4) After placing the corundum crucible in the resistance furnace, fasten the quartz condenser above the crucible to recover the rapidly volatilized NH 4 Cl.

[0049] (5) After keeping the reaction at 500°C for 5 hours, UO was detected 2 Almost insoluble, just deposited on the bottom of LiCl-KCl molten salt, the dissolution rate is 7% according to ICP-AES measurement.

[005...

Embodiment 3

[0053] Through the two types of tests exemplified in Example 1 and Example 2, the inventors found a method based on the addition of ammonium chloride and the isolation of air to separate uranium dioxide and lanthanide oxides. The following is an example of separation (for the process see figure 2 ).

[0054] (1) Mix 44.8g LiCl and 55.2g KCl evenly, place in an alumina crucible, place in a vacuum drying oven, dry at 150°C for more than 72 hours, transfer to an argon-protected glove box for standby, glove box water, The oxygen content is less than 1ppm.

[0055] (2) Add 0.3g UO 2 ,0.5g Sm 2 o 3 ,0.5g Eu 2 o 3 ,0.5g CeO 2 with 10g NH 4 Cl is mixed evenly, and placed in a flat-bottomed container made of a 300-mesh molybdenum filter. The top of the container is tied tightly with molybdenum wire, and the molybdenum wire is drawn out from the hole at the top of the quartz condenser.

[0056] (3) Heat the LiCl-KCl salt prepared in step (1) to 500°C in a glove box. After the...

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PUM

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Abstract

The invention provides an application of ammonium chloride for separating uranium dioxide and lanthanide oxide, and provides a method for separating uranium dioxide and lanthanide oxide by using ammonium chloride. The method is characterized in that ammonium chloride is added in a reactant containing uranium dioxide and lanthanide oxide, the materials are contacted with chloride molten salt at thetemperature of 450-600 DEG C, the reactant and the chloride molten salt are controlled for isolating air, and the uranium dioxide and lanthanide oxide are separated. The application of the ammonium chloride in separation of dioxide solves the difficult dissolving problem of uranium dioxide in molten salt, and the reaction condition is controlled to separate the uranium dioxide and lanthanide oxide. The method can directly realize UO2 dissolution in a chloride molten salt system, and can be carried out in air during a dissolving process, other deposition is not formed, other impurity is not introduced, strongly corrosive gas is not employed, and a whole process has the advantages of simple operation, mild reaction condition, and strong practicality.

Description

technical field [0001] The invention belongs to the technical field of nuclear technology, and in particular relates to a method for separating a mixture containing radioactive substances. Background technique [0002] Dry reprocessing technology has obvious advantages for the future advanced nuclear fuel cycle. Currently, the most promising dry reprocessing technology is molten salt electrolytic refining technology. This technology mainly uses chloride molten salt as the medium, and uses electrochemical methods to recover the actinide elements in the spent fuel under high temperature conditions, and at the same time realize the separation from the fragment elements. It has the advantages of radiation resistance, low criticality risk, and less radioactive waste. However, the classic molten salt electrorefining process is mainly aimed at the reprocessing of metal spent fuel, and cannot be directly processed for oxide spent fuel, because the solubility of the oxides of actini...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C19/48
CPCG21C19/48Y02E30/30Y02W30/50
Inventor 石伟群刘雅兰罗利霞
Owner INST OF HIGH ENERGY PHYSICS CHINESE ACADEMY OF SCI
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