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Method for releasing and controlling uranium-containing calcium fluoride slag

A uranium calcium fluoride and release control technology, applied in the field of radioactive waste treatment, can solve the problems of complex process steps, many side reactions, and waste water, and achieve the effect of simple process operation, scientific and reasonable steps, and solution to storage pollution

Pending Publication Date: 2021-12-28
CHINA INST FOR RADIATION PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has the advantages of low cost, but there are problems such as complicated process steps, more waste water, serious pollution, and more side reactions in the separation and purification process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0055] 1) Preparation of mixed molten salt with low melting point: Grind uranium-containing calcium fluoride slag to a uniform powder with a particle size of less than 1 mm, and add molten salts NaF and MgF with low melting point 2 and other components as a flux, the CaF 2 -NaF-MgF 2 etc. Mix evenly in a certain proportion, calculate and obtain the lowest eutectic point.

[0056] 2) Assembling of the metal mesh basket: make an integral porous mesh basket made of inert metal molybdenum / tungsten / platinum, etc., with a pore size greater than 200 meshes, connect the upper end of the mesh basket to the inert metal molybdenum / tungsten / platinum as a connecting device and follow-up Anode during electrolysis.

[0057] 3) Separation of solid waste and molten salt: place the uniformly mixed uranium-containing molten salt in a porous mesh basket, place the porous mesh basket in a magnesium oxide crucible, and place them together in a resistance furnace, and the temperature rises to 100-...

Embodiment 1

[0063] 70gKF and 100g of uranium-containing CaF 2 The slag is dried in a vacuum muffle furnace for 72 hours, mixed evenly as a molten salt system, stored in a stainless steel porous mesh basket, heated for several hours, and subjected to solid-liquid separation. The solid in the mesh basket is directly taken out for disposal, and the final product can be obtained. Calcium fluoride product with a purity >95%.

Embodiment 2

[0065] 172g of LiF and 100g of uranium-containing CaF 2 Dry the slag in a vacuum muffle furnace for 72 hours, mix it evenly as a molten salt system, place it in a crucible and heat it for several hours, put all the electrodes into the molten body, the pole distance is 30mm, and then the voltage is 2.0V to -2.4V Keep it under high temperature for 10 minutes to remove impurities. After replacing the molybdenum / tungsten / platinum wire, keep it for 30 minutes, and conduct appropriate electrochemical tests to ensure that the performance of each device is stable. Use a constant potential electrolysis method to control the potential at 2.4V to -3.2V. Electrolyze for 4-40 hours, remove the cooled electrode, and obtain a calcium fluoride product with a purity > 99.9% after release.

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PUM

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Abstract

The invention belongs to the technical field of radioactive waste treatment, and relates to a method for releasing and controlling uranium-containing calcium fluoride slag. The method comprises the following steps of (1) grinding the uranium-containing calcium fluoride slag, adding a molten salt system with a low melting point as a fluxing agent, and uniformly mixing; (2) placing the mixture obtained in the step (1) in a porous mesh basket, placing the porous mesh basket in a crucible, heating in a sealed environment, and removing the porous mesh basket and infusible solids in the porous mesh basket; (3) continuously heating the mixed molten salt in the crucible, electrolyzing, and enriching solid products of metal and alloy on a cathode; and (4) putting the cathode in the step (3) and the enriched product thereof into the porous net basket, taking the porous net basket as an anode, taking metal as the cathode, and carrying out electrolysis under the system of the molten salt with the low melting point, so as to obtain the metal uranium and the alloy thereof on the cathode. By means of the method, the uranium and the calcium fluoride can be separated from the uranium-containing calcium fluoride slag in a simple-process-operation, low-cost, high-efficiency and environment-friendly mode.

Description

technical field [0001] The invention belongs to the technical field of radioactive waste treatment, and relates to a method for releasing and controlling calcium fluoride slag containing uranium. Background technique [0002] As a clean, safe and economical energy, nuclear energy has brought convenience to people's life and production, but the safety management of polluted materials brought by it cannot be ignored. In the uranium conversion and purification process of the nuclear fuel cycle, a large amount of uranium-containing calcium fluoride contaminated materials will be produced, part of which comes from the crucible used in the production process (the material is CaF 2 ) container, and the other part is the by-product of the uranium purification process (commonly known as "Wowotou"). The uranium content of the former is not high, but it cannot meet the requirements of clearance control; the uranium content of the latter is relatively high, and from the perspective of ...

Claims

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Application Information

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IPC IPC(8): C25C3/34C25C3/36C01F11/22
CPCC25C3/34C25C3/36C01F11/22C01P2006/80
Inventor 蒋可为王永仙郭丽潇梁宇梁栋武明亮张文俊刘东高志婷高亚华张宇航李帅帅赵晋杰崔玉杰
Owner CHINA INST FOR RADIATION PROTECTION