Recovery method of uranium and fluorine in uranium hexafluoride alkali absorption liquid waste liquid

Abstract

The invention discloses a recovering method for uranium and fluorine in uranium hexafluoride alkali absorption solution waste liquid. According to the recovering method, the uranium hexafluoride alkali absorption solution waste liquid is firstly acidized through acid, the pH is equal to 2.7-5.5 through adjustment, then macromolecule adsorbent (polystyrene-cyclohexyl amino maleic acid) is added to finish UO22+ adsorption, solid-liquid separation is performed, so that desorption is performed on obtained solids through acid with concentration larger than 1M to recover UO22+, Na2CO3 is added into the remaining solution to perform a next cycle of uranium hexafluoride elution, and after five or more cycles, the solution is rich in F- high in concentration. NaC1 is added into the solution, so that the solution is saturated, and NaF is precipitated due to the fact that the solubility is reduced, NaF solids are obtained through filtering and recovering, CaC12, or CaO or Ca (OH)2 solids or saturated solutions are then added into the solution, so that the residual F- forms CaF2 sediment, and fluoride removal is performed deeply. Finally, the uranium and the large amount of fluoride in the uranium hexafluoride alkali absorption solution waste liquid are recovered. Uranium in the radioactive waste liquid is recovered, zero drainage of the waste liquid is achieved, the drainage of the waste liquid reaches the national standard, and meanwhile the problem that in a traditional fluoride removal technology, a large amount of calcium fluoride is difficult to filter is solved.

Description

technical field [0001] The invention relates to recovery of radioactive element uranium and sewage treatment, in particular to a method for recovery of uranium and fluorine in uranium hexafluoride gas alkali absorption liquid waste liquid, belonging to the field of nuclear fuel recovery and hydrometallurgy. Background technique [0002] Uranium hexafluoride is a lively and highly reactive substance, usually a white solid, highly volatile, with a sublimation temperature of 56.54 °C, and is currently the only uranium that is both stable and highly volatile at room temperature compound. As an important intermediate in the nuclear fuel production process, it is also the only one currently available for gas centrifugal separation and extraction 235 Uranium compounds. The fluorine atoms in uranium hexafluoride can be partially or completely replaced by other electronegative atoms, such as F / O (fluorine and oxygen) replacement reaction to generate oxyfluoride. One of the most ty...

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Problems solved by technology

[0005] The hydrolysis reaction of uranium hexafluoride is very sensitive, resulting in a lot of uranium in the waste generated in the production process. Leakage is easy to occur during storage and other processes, which poses a problem for the treatment of radioactive waste liquid

The eluent contains more than 30 mg / L of uranium, and it must be diluted with a large amount of tap water to meet the processing requirements of the existing metal uranium recovery process. After adsorption, extraction, stripping, neutralization and precipitation, the waste liquid meets the national discharge standard and is discharged. , which greatly increases the final discharge of waste liquid, and the process is cumbersome, the cost is high, and the treatment result is not ideal (see: Zhang Xilin, uranium, fluorine-containing tail gas leaching and eluent regeneration process research, small circular economy academic seminar Papers Collection, 2009, 182-196)

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