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Method for recovering ammonium nitrate from radioactive waste liquid

A technology of radioactive waste liquid and ammonium nitrate, which is applied in the direction of ammonium nitrate, etc., to achieve the effect of compact process flow, easy operation and low cost

Active Publication Date: 2013-09-25
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To sum up, in the common ammonium nitrate recovery method, the trace amount of radioactive uranium is a serious interference factor for recovery and treatment, and there is still a lack of an effective method for the recovery of ammonium nitrate in radioactive waste liquid

Method used

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  • Method for recovering ammonium nitrate from radioactive waste liquid

Examples

Experimental program
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Effect test

Embodiment 1

[0029] During the production of a batch of spherical fuel elements, 25 liters of process waste liquid needs to be treated. The ammonia concentration in the waste liquid is 10g / L, the uranium content is 3.7mg / L, and the COD value of high molecular organic matter is 1.0×10 4 , the concentration of ammonium nitrate is 68g / L. In order to realize the recovery of ammonium nitrate in the waste liquid, the adopted scheme is as follows: firstly, the waste liquid is distilled to remove ammonia, and then the solid impurities and high-molecular organic matter in the waste water are removed by filtration, and then the uranium is removed by silica gel adsorption. Finally, ammonium nitrate is recovered by evaporation and crystallization. see process figure 1 .

[0030] The waste liquid of this process is left standing in the waste liquid tank. After the solid matter in the waste liquid is precipitated, the supernatant liquid is sent to the heat exchanger with a pump for distillation to re...

Embodiment 2

[0036] The ammonia concentration in the waste liquid to be treated is 10g / L, the uranium content is 4.2mg / L, and the COD value of high molecular organic matter is 3.0×10 4 , the concentration of ammonium nitrate is 59g / L.

[0037] The waste liquid of this process is left standing in the waste liquid tank. After the solid matter in the waste liquid is precipitated, the supernatant liquid is sent to the heat exchanger with a pump, and the ammonia is removed by distillation. The ammonia mass concentration in the waste liquid after the ammonia removal is reduced to 0.2 %.

[0038] The waste liquid after ammonia removal is pressurized to 0.35MPa by a pump, and passes through activated carbon, microfiltration membrane (pore size: Φ10μm) and ultrafiltration membrane (pore size: Φ0.5μm) in sequence to remove solid particles with a particle size of micron in the waste liquid and some macromolecules. The COD value in the treated waste liquid is 1.1×10 2 , The removal rate of polymeri...

Embodiment 3

[0042] The concentration of ammonia in the waste liquid to be treated is 10g / L, the content of uranium is 10mg / L, and the COD value of high molecular organic matter is 3.0×10 4 , the concentration of ammonium nitrate is 70g / L.

[0043] The processing steps are the same as in Example 2. After crystallization and filtration, the crystallization raffinate was collected, and the uranium content in the raffinate was measured to be 0.13mg / L, then the raffinate was pumped into the silica gel column by the peristaltic pump again, and the time of the raffinate in the silica gel column was 20min. The residual liquid after passing through the silica gel column is tested for uranium content, and the uranium content is lower than 0.02mg / L, and the secondary crystallization is carried out. The primary and secondary crystals were collected to finally obtain 163.2 g of ammonium nitrate product (purity 99.6%). The second crystallization residue is reduced to 2% of the original volume, and th...

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Abstract

The invention provides a method for recovering ammonium nitrate from a radioactive waste liquid. The method comprises the following steps: 1) filtration processing: after standing and clarification of the waste liquid, taking a supernatant liquid to filter successively through activated carbon, a microfiltration membrane and an ultrafiltration membrane; 2) silica gel adsorption: collecting the waste liquid after filtration, adjusting pH value of the waste liquid to 6.5-8.5, then pumping the waste liquid into a silica gel column to make uranium in the waste liquid being selectively absorbed; 3) evaporation crystallization processing: heating the waste liquid after the processing of the Step 2) to 80 to 100 DEG C to evaporate the water, stopping heating and standing for the first crystallization, when the volume of the waste liquid for processing is concentrated to 15-30% of the original volume. In the method for recovering the ammonium nitrate from the radioactive waste liquid, a step by step processing manner is adopted to solve the problem of complex compositions of the waste liquid; interferences of organic matters and the uranium in the waste liquid can be eliminated through the filtration and the silica gel preprocessing step, and ammonium nitrate recovery rate can reach above 90%. The method has the advantages of compact technological processes, no pollution, simple operation and low cost.

Description

technical field [0001] The method belongs to the chemical industry field of waste liquid treatment in a nuclear fuel cycle system, and specifically relates to a method for recovering ammonium nitrate in low-radioactive high-concentration ammonium nitrate waste liquid. Background technique [0002] High temperature gas-cooled reactor spherical fuel element ceramic UO 2 The core is prepared by the sol-gel method, and its main process includes: dissolving, boiling gel, dispersing-gelling, aging-washing-drying, roasting-reduction, sintering, screening and so on. Among them, the stages of dispersion, aging and washing will produce a large amount of process waste liquid, and its main components are trace amounts of uranium, organic matter and high-concentration ammonium nitrate and other substances. Ammonium nitrate is spherical fuel element ceramic UO 2 One of the main raw materials for core preparation needs to be recycled. The radioactivity in the generated waste liquid is l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01C1/18
Inventor 王阳陈晓彤权英刘兵唐亚平
Owner TSINGHUA UNIV
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