Effect Of Aluminum On Rare Earth Extraction In P507System

China is rich in rare earth resources, it has the highest reservation and production of rare earth resource in the world. P507is mainly used to separate and putify the rare earth products in rare earth solution from decomposed-leached rare earth material. But the emulsification is caused by the impurities in feed liquid in the process of extracting rare earth, result in the loss of tens of millions of dollars synthetically every year and the quality of rare-earth product is effected by impurity. However,aluminum ion is the important factors which cause emulsion of extractant and effect the quality of rare-earth product. But there is no effective solution to separate rare earth from aluminum to avoid emulsification of extractant and improve quality of rare earth production.In this paper, the concentration of aluminum and rare earth in extraction raffinate solution and stripping solution is determined by chemical analysis at different extraction situation. The distribution of aluminum and the effect of aluminum on the rare earth extraction are discussed in process of aluminum and rare earth extraction with saponification P507. The purpose is to understand the mechanism of extracting of aluminum and the mechanism of aluminum effect on rare earth extraction. Then it probably provide theoretical basis to stuy method of prevent emulsification, and supplying the basis to analyse real cause of the effect of aluminum on rare earth products.The results of saponification P507extracting only aluminum ion show that, the extraction amount of aluminum ions increases with the concentration of aluminum in the feed solution increasing and going to levele and extraction rate is depressed gradually. Extraction amount and extraction rate increase with saponification value and pH value rurning to big.Temperature had little effect on the extraction of aluminum, but it plays an important role on the stripping rate of aluminum, in the temperature of30～40℃, the stripping rate of aluminum is relatively low, result in some aluminum ions left and accumulated in the organic phase, finally affect the progress of extraction, but the temperature increased is beneficial to the stripping rate of aluminum.Results of saponification P507load different concentrations of Al extracting of rare earth show that under a certainty saponification value, the total content of aluminum and rare earth load in P507is basically the same,and the distribution ratio of rare earth decrease with the Al content loaded in organic phase increasing. The stripping rule of Al in P507loaded of aluminum and rare earth is similar to the stripping rate of aluminum in P507load aluminum only. Therefore, aluminum is also accumulated in organic phase in the process of extraction rare earth, than affect the progress of extracting of rare earth elements, or even result in emulsification.The extracted process of saponification P507and aluminum is investigated, and the results show that the organic phase is not emulsification with aluminum concentration less than0.741mol/L at pH≤3,and when the aluminum concentration is surpass0.374mol/L, the organic phase is emulsification at pH>3.When the concentration of residual aluminum in the aqueous phase close to zero,the water phase shows the phenomenon of turbidity, and the phenomenon of turbidity tend to disappear with higher concentrations of aluminum.The results of observation by polarizing microscope show that extraction raffinate phase cloudy is due to the phenomenon of the formation of O/W emulsion in the extraction raffinate, which has little effect on the extraction process. Organic phase cloudy is due to the existence of a large number of W/O emulsion drops in organic phase, which will affect the extraction process to continue.The analysis of extraction of aluminum and rare earth analysed by infrared spectroscopy show that:Al ions exchange with H of P-O-H for cation exchange reaction, while P=O bond involve in the coordination. When P507loaded of aluminum extract of rare earth, P=O group characteristic peaks wavenumbers turn to red shift,and red shift decreased with the increasing of the aluminum loaded in organic phase. Which indicated that aluminum load in the organic phase hinder P=O groups in coordination with the rare earth,resulting in the capacity of rare earth elements extracted decrease with the increase of the amount of aluminum loaded in organic phase.The stripping situation of the organic phase loaded of aluminum and rare earth is similar to the organic phase only loaded aluminum, so aluminum is also not stripped cleanly.