Studies On Extraction Of U(Ⅵ) By Picolinamide

Research and development of new extraction system for the development of the nuclear industry is of great significance, pyridyl amide extracting agents are easy to be synthesized, resistant to radiation, etc., it has a significant advantage in the post-processing of nuclear fuel. In this paper, three pyridine amide extracting agents were synthesized, we studied their performance extraction of U(VI), and through the slope method explored the extraction mechanism. The paper was divided into four parts:Part I: Literature review, the sources of waste water containing uranium, processing method, and the advantages of solvent extraction, the simple introduction of the classification of progress and extraction agent is described.Part II: Synthesis and characterization of the extraction solvent N,N’-(1,2-ethyl)-dipicolinamide, acidity, compared extractant concentration, salting-out agent concentration, temperature and other factors on extraction affect the results were investigated, the results showed that: in a diluent chloroform and the aqueous phase: organic phase = 1.5, extractant concentration was 0.04 mol/L, p H value of 6, the reaction reached extraction equilibrium in 30 min, best oscillation extraction distribution ratio was 6.2, the extraction reaction was exothermic, KCl do salting-out agent reached the best extraction effect. Extraction agent complex with UO22+ bimolecular.Part III: Synthesis and characterization of the extraction solvent N,N’-(1,4-phenylene)-dipicolinamide, acidity, time, extractant concentration, salting-out agent concentration, temperature and other factors on extraction affect the results were investigated, the results showed that: in a diluent chloroform extraction agent, at a concentration of 0.04 mol/L, the aqueous phase/organic phase = 1.5, p H value of 6, the extraction showed best result, up oscillation 40 min extraction reached equilibrium, extraction distribution ratio was 9, the extraction reaction was exothermic, KCl as salting agent showed best extraction result, salting-out agent concentration was 0.25 mol/L got the extraction distribution ratio of 12 or more, extracting agent and UO22+ complexed bimolecularly.Part IV: Synthesis and characterization of the extraction solvent N, N’-(2,6-pyridyl)-dipicolinamide(PRDPA), examined the influence of acidity, time, extractant concentration, salting-out agent concentration, temperature and other factors on the extraction efficiency, the results showed that: in a diluent chloroform extraction agent concentration of 0.025 mol/L, p H value of 6, we got best extraction result, oscillation 60 min reached the extraction equilibrium, extraction distribution ratio was 7.3, the extraction reaction was exothermic, NH4 Cl as salting-out agent showed the best extraction, extraction complexes possible structure was 2UO2Cl2 ? 3PRDPA.