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CN-118324494-B - Method for curing silver iodide, ceramic curing body and application

CN118324494BCN 118324494 BCN118324494 BCN 118324494BCN-118324494-B

Abstract

The application discloses a method for curing silver iodide, a ceramic curing body and application thereof. According to the method for curing silver iodide, provided by the application, in consideration of the wide application of silver iodide in radioiodination, silver iodide is directly used as a raw material, mixed with barium source salt and sodium iodide salt raw materials, and subjected to steps of dry pressing, reaction, sintering and the like to prepare a ceramic curing body so as to cure radioiodine in the ceramic curing body. The method has the advantages of simple process, low cost and strong applicability, the content of the curable silver iodide is 4.44-35.40 wt%, and compared with the traditional iodine curing method, the method has higher practicability and can be applied to the treatment of radioactive iodine waste.

Inventors

  • SUN SHIKUAN
  • ZHAO YI
  • Ai Qu
  • HUANG YUJIA
  • WANG XIUCAI
  • CHEN MIN

Assignees

  • 佛山科学技术学院

Dates

Publication Date
20260505
Application Date
20240417

Claims (8)

  1. 1. A method of curing silver iodide comprising the steps of: Mixing silver iodide, barium source salt and sodium iodide salt, and performing dry press molding to obtain a first coarse blank; Placing the first coarse embryo at 400-600 ℃ for in-situ reaction to obtain a second coarse embryo containing Ba 2 (Ag x Na 1-x )IO 6 ; sintering and densifying the second rough blank; The barium source salt is one of barium carbonate, anhydrous barium hydroxide and octahydrate barium hydroxide; The sodium iodized salt is one of sodium iodate, sodium periodate and sodium iodide; The molar ratio of the barium source salt, the silver iodide and the sodium iodide salt is 2:x (1-x), wherein x is more than or equal to 0.1 and less than or equal to 0.9.
  2. 2. The method of claim 1, wherein the in-situ reaction conditions further comprise a temperature rise rate of 2-10 ℃ per minute and an in-situ reaction time of 1-10 hours.
  3. 3. The method of claim 1, wherein the conditions for sintering densification comprise a temperature rise rate of 2-10 ℃ per minute, a sintering temperature of 800-1100 ℃ and a sintering time of 1-10 hours.
  4. 4. The method according to claim 1, wherein the dry press molding conditions include a dry press pressure of 10 to 80 MPa.
  5. 5. The method according to claim 1, wherein the silver iodide, the barium source salt and the sodium iodide salt are all powder with a particle size of 10nm to 100 μm.
  6. 6. The ceramic cured body prepared by the method according to any one of claims 1 to 5, wherein the chemical formula of the ceramic cured body is Ba 2 (Ag x Na 1-x )IO 6 , and the ceramic cured body has a periodate double perovskite structure, and x is more than or equal to 0.1 and less than or equal to 0.9.
  7. 7. Use of the method of any one of claims 1 to 5 for the treatment of radioiodinated waste.
  8. 8. A method for treating radioactive iodine waste, comprising the steps of: Adsorbing the radioiodinated waste with a silver-containing adsorbent to convert the radioiodinated waste to radioiodinated silver; curing the radioactive silver iodide using the method of any one of claims 1 to 5.

Description

Method for curing silver iodide, ceramic curing body and application Technical Field The application relates to the technical field of radioactive waste treatment, in particular to a method for curing silver iodide, a ceramic curing body and application thereof. Background Nuclear energy has been used in a variety of fields as a high-efficiency energy source. However, during the fission process of nuclear fuel, various radioactive wastes are generated, and how to safely dispose of these radioactive wastes is critical for sustainable development of nuclear energy. Radioactive iodine is the main radioactive waste generated by nuclear power station fuel fission, and meanwhile, the iodine has the characteristic of volatility. The main hazard of radioactive iodine is strong toxicity, strong volatility, easy diffusion, easy absorption by human body and enrichment in thyroid gland of human body, thereby causing thyroid radiation injury and causing serious hazard to human health. Currently, a well-known method in the art that can effectively treat radioactive iodine waste is to efficiently adsorb it to convert it into a stable solid, and then further sinter it into a stable solidified body. Among them, common iodine adsorbents are silvered silica gel or silvered zeolite, etc. The silver-coated zeolite has high iodine adsorption efficiency and wide application, and the radioactive iodine adsorbed on the silver-coated zeolite mainly exists in the form of silver iodide (AgI). The melting point of AgI is 558 ℃, the boiling point is 1506 ℃, the thermal stability is poor, pyrolysis is easy to occur at high temperature, so that silver iodide cannot be directly used as a radioactive iodine solidified body, the silver iodide is required to be further treated to be converted into a stable solidified body which can be placed for a long time, deep geological burying is performed, and ecological environment pollution is avoided. Aiming at the high hazard of radioactive silver iodide (AgI), a plurality of measures are adopted at present to cure the iodine adsorbent containing silver iodide, and the main treatment methods are cement or glass curing and the like. Although the method can treat the radioactive iodine to a certain extent, the obtained solidified body still has a plurality of problems of poor stability, easy secondary pollution, low radioactive iodine content and the like. Disclosure of Invention The application aims to solve the problems that the silver iodide solidified body prepared in the prior art is poor in stability, easy to cause secondary pollution and low in radioactive iodine content, and further provides a method for solidifying silver iodide, a ceramic solidified body and application. In order to achieve the aim of the application, the application adopts the following technical scheme: In a first aspect, the present application provides a method of curing silver iodide comprising the steps of: Mixing silver iodide, barium source salt and sodium iodide salt, and performing dry press molding to obtain a first coarse blank; placing the first rough blank at 400-600 ℃ for in-situ reaction to obtain a second rough blank; And sintering and densifying the second rough blank. In an alternative embodiment, the molar ratio of the barium source salt, the silver iodide and the sodium iodide salt is 2:x (1-x), based on the barium element, the silver element and the sodium element, wherein 0.1≤x≤0.9. Illustratively, x may have a value of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 07, 0.8, or 0.9. In an alternative embodiment, the barium source salt includes at least one of barium carbonate, barium nitrate, anhydrous barium hydroxide, barium octahydrate, and barium sulfate; And/or the sodium iodized salt comprises at least one of sodium iodate, sodium periodate and sodium iodide. In an alternative embodiment, the conditions of the in-situ reaction further comprise a heating rate of 2-10 ℃ per minute and an in-situ reaction time of 1-10 hours. Illustratively, the first rough blank is placed in a muffle furnace, the temperature is raised to 400-600 ℃ at a temperature rise rate of 2-10 ℃ per minute, the temperature is kept for 1-10 hours, and in-situ reaction is completed to generate Ba 2(AgxNa1-x)IO6. Preferably, the reaction equation of the in situ reaction is at least one of the following equations: 2Ba(OH)2 + xAgI + (1-x)NaIO4 + 2xO2 = Ba2AgxNa1-xIO6 + 2H2O; 2BaCO3 + xAgI + (1-x)NaIO4 + 2xO2 = Ba2AgxNa1-xIO6 + 2CO2; 2Ba(NO3)2 + xAgI + (1-x)NaIO4 + 2xO2 = Ba2AgxNa1-xIO6 + 4NO2; 2Ba(OH)2•8H2O+ xAgI + (1-x)NaIO4 + 2xO2 = Ba2AgxNa1-xIO6 + 18H2O; 2BaSO4+ xAgI + (1-x) NaIO4 + 2xO2 = Ba2AgxNa1-xIO6 + 2SO3; 2Ba(OH)2 + xAgI + (1-x)NaIO3 + (0.5+1.5x)O2 = Ba2AgxNa1-xIO6 + 2H2O; 2BaCO3 + xAgI + (1-x)NaIO3 + (0.5+1.5x)O2 = Ba2AgxNa1-xIO6 + 2CO2; 2Ba(NO3)2 + xAgI + (1-x)NaIO3 + (0.5+1.5x)O2 = Ba2AgxNa1-xIO6 + 4NO2; 2Ba(OH)2•8H2O+ xAgI + (1-x)NaIO3 + (0.5+1.5x)O2 = Ba2AgxNa1-xIO6 + 18H2O; 2BaSO4+ xAgI + (1-x) NaIO3 + (0.5+1.5x)2O2 = Ba2AgxNa1-xIO6