Correlation complexation constants of Ce⁴⁺ and F⁻

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 CeF₂²⁺=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.