Abstract: In the process of saponified P507 system extraction of rare earth， the emulsification is a normal phenomenon in solvent extraction， resulting in an obvious decrease of REs’ extraction efficiency， high cost， etc. The extraction of Si， the emulsification of silicon (Si) in two phases and the effect of the saponified P507 loaded with Si on the extraction of rare earths were investigated. The results demonstrated that only a little Si enters the organic phase. The emulsification of Si has a direct influence on the La extraction， and the extraction capacity of La reduces 7g/L after four times mixing under the circumstances of organic phase continuation. The FTIR analysis illustrates that Si is not involved in reaction with saponified P507; the shifts of water peak and hydroxyl indicate that there is a closely relationship between the emulsification and extraction process.

Key words: Si, saponified P507, rare earth, emulsification, extraction