Abstract:In recent years, the phenomenon of misaligned separation of cerium components generally appears in the process of extracting and purifying praseodymium neodymium series compounds. So far, there are no relevant report on the distribution of Ce(Ⅳ) in organic phase of each functional segment and the correlation between diluent selection and the misaligned separation of cerium components in rare earth smelting process. Using the classic cerium praseodymium separation process as a theoretical model to systematically study the distribution patterns and influencing factors of Ce(Ⅳ) in various extraction functional segments, analyze the chemical composition and characteristics of diluent, and measure the inhibitory effect of different diluents on Ce(Ⅳ) in organic phase. The results show that the acidity of the aqueous phase, element partitioning and extraction stages have obvious influence on Ce(Ⅳ) content in the organic phase. The inhibitory effect of diluent selection on Ce(Ⅳ) in the organic phase is affected by its chemical composition, and its inhibitory effect sequence is kerosene > sulfonated kerosene > dissolved oil. In the actual industrial production process, the formation of Ce(Ⅳ) in organic phase can be inhibited by adding appropriate amount of kerosene with high bromine value or adjusting some active components in diluent. This study has certain practical guiding significance for the subsequent process improvement and ensuring the quality stability of praseodymium neodymium series products in the rare earth extraction and separation process.