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Method for removing nitric acid and nitrates from high-level radioactive liquid waste

A high-level waste liquid and nitrate technology, which is applied in radioactive purification, nuclear engineering, etc., can solve the problems of high energy consumption and high requirements for electrode corrosion resistance, and achieve the effects of reducing the risk of explosion, high safety and stability, and easy implementation

Inactive Publication Date: 2015-04-15
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The energy consumption of electrochemical denitrification is large, and the requirements for electrode corrosion resistance are high

Method used

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  • Method for removing nitric acid and nitrates from high-level radioactive liquid waste
  • Method for removing nitric acid and nitrates from high-level radioactive liquid waste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Step 1. Synthesize urea-formaldehyde resin (UF resin) with a molar ratio of formaldehyde and urea of ​​3:1. Pour all the formaldehyde 243.24g into the reaction kettle, add the first batch of urea 21.82g, adjust the pH value to 7.5, mix and stir, heat up to 95°C, react for 1h; adjust the pH value to 4.0 and continue the reaction for 1h; cool down to 85°C , add the second batch of urea 8.18g, adjust the pH to 7.0, and react for 1h; cool down to 75°C, add the third batch of urea 30g, react for 1h, and the reaction is completed to obtain UF resin.

[0029] Step 2, configure a nitric acid solution with a concentration of 7mol / L, and add NaNO to it 3 , Ba(NO 3 ) 2 , Sr(NO 3 ) 2 , CsNO 3 , so that the concentrations are 0.076 mol / L, 0.02 mol / L, 0.016 mol / L, 0.037 mol / L respectively, forming simulated high-level radioactive waste liquid.

[0030] Step 3, feed ammonia gas and add ammonium chloride to the good simulated high-level radioactive waste liquid configured in step...

Embodiment 2

[0031] Example 2: In Example 1, the concentration of hydrochloric acid in the reaction system was 0.1mol / L, and other conditions remained unchanged, and the removal rate of nitrate reached 27.25%.

Embodiment 3

[0032] Example 3: In Example 1, the concentration of hydrochloric acid in the reaction system was 0.5mol / L, and other conditions remained unchanged, and the removal rate of nitrate reached 39.74%.

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Abstract

The present invention discloses a method for removing nitric acid and nitrates from a high-level radioactive liquid waste. Nitric acid and nitrates are converted to ammonium nitrate; with urea formaldehyde resin as a reducing agent, as NH4NO3 can be easily decomposed into N2, H2O and O2 under the catalysis of H+ and Cl-, the nitric acid and nitrates in the high-level radioactive liquid waste are removed through oxidation-reduction reactions. The method mainly comprises the following steps: (1) UF resins are prepared using a certain ratio of urea and formaldehyde as raw materials and an alkali-acid-alkali process; (2) with ammonia and ammonium salts added, the nitric acid in the high-level radioactive liquid waste can be neutralized and the produced nitrates can be converted into ammonium nitrate which can be easily decomposed by a metathetical reaction; (3) the UF resins are added into the high-level radioactive liquid waste and conduct a denitration reaction under the catalysis of H+ and Cl-. Compared with traditional denitration of high-level radioactive liquid waste, the method in the present invention has a more stable reaction and a lower explosion risk, produces a small amount of NO2, and at the same time the denitrated objects can be both nitric acid and nitrates in the high-level radioactive liquid waste.

Description

technical field [0001] The invention relates to a denitrification method for high-level waste liquid in the nuclear industry field, in particular to a method using ammonium nitrate as an oxidizing agent and urea-formaldehyde resin as a reducing agent. + and Cl - Under the catalytic action of the catalyst, redox reaction is carried out to remove nitric acid and nitrate in high-level radioactive waste liquid. Background technique [0002] High-level waste liquid mainly refers to the aqueous phase extraction raffinate produced by the spent fuel reprocessing plant, which contains a large amount of NaNO 3 , Nd(NO 3 ) 3 , ZrO(NO 3 ) 3 In order to prevent precipitation, the concentration of nitric acid should be maintained above 2M. High-level radioactive waste has the characteristics of strong radioactivity, high heating rate, and high corrosiveness. A small amount of organic matter remaining after the Purex process cycle can undergo uncontrolled combustion-explosion reacti...

Claims

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Application Information

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IPC IPC(8): G21F9/04G21F9/06
CPCG21F9/06
Inventor 唐双凌周蓉杨云飞李燕英鲁彤王泸
Owner NANJING UNIV OF SCI & TECH
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