Method for extracting and preparing nuclear-grade ThO2 powder from rare earth waste residues

A technology for rare earth waste residue and powder, which is applied in the field of extracting and preparing nuclear pure ThO2 powder, can solve the problems of low utilization rate of thorium resources, many radioactive waste water, low recovery efficiency, etc., and achieves good extraction and stripping effect and simple process flow. , the effect of less corrosive equipment

Pending Publication Date: 2021-04-02
CHINA NUCLEAR BAOTOU GUANGHUA CHEM IND
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Problems solved by technology

[0002] In the rare earth dressing and smelting process, thorium is mined together as a companion. Due to the low utilization rate of thorium resources, a large amount of thorium resources are finally stored separately in the form of rare earth waste residues. These rare earth waste residues will not only cause radioactive pollution, but also Serious waste of precious thorium resources, so it is necessary to recycle thorium from rare earth waste slag
[0003] In the traditional recycling process, ThO is extracted and prepared by acid mixing, extraction, precipitation, burning and other processes. 2 Powder, the amount of reagent used in this process is large, the fluorine-containing acid liquid is easy to corrode the equipment, and a lot of radioactive waste water is generated, and the traditional extraction equipment has problems such as low recovery efficiency and high energy consumption.

Method used

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  • Method for extracting and preparing nuclear-grade ThO2 powder from rare earth waste residues

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0071] Step 1. Pretreat the rare earth waste residue, measure its components, add 5-12L deionized water to each kilogram of waste residue to make slurry, and control the temperature of the waste residue slurry at 60-90°C.

[0072] Step 2: adding 2.5-4 mol / L lye to carry out alkaline displacement reaction, the amount of lye added is 120-180% of the normal reaction amount, and the displacement reaction is not less than 3 hours. The generated thorium hydroxide filter cake is subjected to washing operation, the washing temperature is 50-70°C, and the washing times are not less than 3-5 times.

[0073] Step 3, using nitric acid to dissolve the thorium hydroxide filter cake, the dissolution temperature is controlled at 60-90° C., the concentration of thorium ions in the solution is adjusted to 50-300 g / L, and the acidity is adjusted to 1-4 mol / L. Add 3% to 12% H in volume to the thorium nitrate solution 2 o 2 Carry out cerium ion reduction conversion, and use it as an extraction s...

Embodiment 2

[0077] Step 1. Pretreat the rare earth waste residue, measure its components, and make slurry according to the ratio of adding 7L deionized water per kilogram of waste residue.

[0078] Step 2: Control the temperature of the waste residue slurry at 70° C., add 3 mol / L sodium hydroxide solution to carry out alkaline displacement reaction, and carry out the reaction for 2 hours to obtain a thorium hydroxide filter cake. The thorium hydroxide filter cake was washed 4 times with deionized water at 60°C.

[0079] Step 3, add nitric acid to dissolve the thorium hydroxide filter cake, control the dissolution temperature at 80°C, adjust the concentration of thorium ions to 150g / L, adjust the acidity to 2mol / L, and add 5% H 2 o 2 Carry out cerium ion reduction conversion, and use it as an extraction stock solution for later use.

[0080] Step 4: first prepare TBP-kerosene with a volume ratio of 5%, and carry out the operation of removing uranium from the solution, and then prepare TB...

Embodiment 3

[0083] Step 1. Pretreat the rare earth waste residue, measure its components, make slurry according to the ratio of adding 10L deionized water per kilogram of waste residue, and control the temperature of the waste residue slurry at 80°C.

[0084] Step 2: adding 2.5 mol / L sodium hydroxide solution to carry out alkaline displacement reaction, and the reaction was carried out for 3 hours to obtain a thorium hydroxide filter cake. The thorium hydroxide filter cake was washed three times with deionized water at 70°C.

[0085] Step 3, add nitric acid to dissolve the thorium hydroxide filter cake, control the dissolution temperature at 75°C, adjust the concentration of thorium ions to 200g / L, adjust the acidity to 2.5mol / L, and add 8% H 2 o 2 Carry out cerium ion reduction conversion, and use it as an extraction stock solution for later use.

[0086] Step 4: first prepare TBP-kerosene with a volume ratio of 9%, and perform the solution deuranium operation, and then prepare TBP-ker...

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Abstract

The invention belongs to the technical field of radioactive waste treatment, and particularly relates to a method for extracting and preparing nuclear-grade ThO2 powder from rare earth waste residues.The method is used for alkalization treatment of the rare earth waste residues, not only can realize preliminary separation of thorium elements and part of impurity elements, but also can effectivelysolve the problem of equipment corrosion, meanwhile, the generated thorium hydroxide is easily converted into a thorium nitrate solution, and the next extractive purification process is carried out.According to the method, the thorium nitrate is extracted and purified by adopting a centrifugal extraction technology, the method has the characteristics of high recovery rate, continuous operation,low energy consumption and the like, the thorium elements are efficiently separated from other rare earth elements, and therefore the method has important significance in extracting and preparing nuclear-grade ThO2 powder from the rare earth waste residues.

Description

technical field [0001] The invention belongs to the technical field of radioactive waste treatment, and in particular relates to a method for extracting and preparing nuclear pure grade ThO from rare earth waste slag. 2 powder method. Background technique [0002] In the rare earth dressing and smelting process, thorium is mined together as a companion. Due to the low utilization rate of thorium resources, a large amount of thorium resources are finally stored separately in the form of rare earth waste residues. These rare earth waste residues will not only cause radioactive pollution, but also The precious thorium resources are seriously wasted, so it is necessary to recycle thorium from rare earth waste residues. [0003] In the traditional recycling process, ThO is extracted and prepared by acid mixing, extraction, precipitation, burning and other processes. 2 Powder, the amount of reagent used in this process is large, the fluorine-containing acid liquid is easy to cor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B60/02C22B7/04C22B3/44C22B1/02C22B3/38C22B3/06
CPCC22B60/0291C22B7/04C22B7/006C22B7/007C22B3/44C22B1/02Y02P10/20
Inventor 张凡李涛刘伟郭波龙盖石琨王昱人郝治国于晓波
Owner CHINA NUCLEAR BAOTOU GUANGHUA CHEM IND
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