Correlation complexation constants of Ce4+ and F−

Abstract

Measured CeFn (n=1, 2, 3) complexation constant and solubility product constant of CeF4 and Na2CeF6 by ICP-AES and UV spectrophotometer, when Ce4+ and F− complexation reaction in water medium and nitric acid medium respectively, and the effects of Re3+and nitric acid concentration on Ce4+ and F− complexation reaction were studied. The experimental results show that the first-order complexation constant of Ce4+ and F− is CeF3 +=6.94*106, the second-order complexation constant is CeF2 2+=4.541*1011, and the third-order complexation constant is CeF3 +=6.232*1014. Compared with the complexation reaction of Ce4+ and F− in water medium and nitric acid medium, the complexation reaction of Ce4+ and F− in nitric acid medium is better. Re3+ appears, which affects the complexation reaction between Ce4+ and F−. When in nitric acid medium, the higher the concentration of nitric acid, the more unfavorable the complexation of Ce4+ and F−. The study of the relevant physical constants of Ce4+ and F− in this paper can be helpful for the separation of Ce4+ and F−, enrich the physical and chemical information of rare earth elements, and provide the basic theoretical basis for the rare earth fluoride that is difficult to be separated and recovered from the tailings, so as to reduce the harm to the soil environment.