Effect Of Silicon&Iron On Extracting Rare Earth In Saponification P507System

Saponification P507-kerosene-RECl3system plays an important role in the separation of rare earth element, the system is currently the main system all around the world, However, emulsion formation has a bad effect on the continuous producing process, which bring about a series of problems, like low productivity, high-cost and quality fluctuation of end-product, eventually caused comprehensive loss at the cost of millions dollars. The impurities Fe3+, Al3+, Si4+and F-are proved to be the main causes of emulsion, therefore it’s necessary to detect their physical and chemical behavior, analyse the mechanism of emulsion, and finally take the effective measures to prevent the emulsification.Based on the study of effect on the aluminium on extracting rare earth in the saponification P507system, the major research works in the paper include that:investigate the influence of acidity, metal ions concentration and extraction temperature on saponification P507extracting silicon and iron; explore the mechanism of silicon, aluminium and iron through the investigation of the influence of loading factor on the rare earth extraction process, provide the theory guident industrial production control and eliminate emulsification.The saponification P507extraction of single silicon results show that the content of silicon has little dependence with the increment of silicon concentration, temperature and pH value, and the max load of silicon is just0.35g/L. The silicon ions were distributed in both organics and water-phase, and silicon in the organics can not be eliminated by chlorhydric acid. The polarization microscopy indicates that the turbid phenomenon in water-phase is the origin of the formation of the O/W emulsion when C(Si4+)<0.2g/L in the feed solution; and the turbid phenomenon in the organic phase is the root of the formation of W/O emulsion when C(Si4+)>1g/L. The further FT-IR analysis illustrates that the Si4+was involved into organics-phase by means of "carry"; silicon and aluminum are distributed into in organic phase, the extraction content of Al imposes a greater influence than that of Si on the rare earth extraction, the existence of Si can promote the emulsion in the organics, Al in the organics-phase can be removed by stripping with HCl, but Si is difficult to eliminate.The results of saponification P507extracting iron ion show that the iron content increases with the reduction of acidity, the increment of C(Fe3+) in the feed solution and extraction temperature with a max capacity of14.4383g/L; iron can be extracted by saponification P507even at the condition of high acidity; iron extracted into the organics-phase can be removed by stripping with HCl. The polarization microscopy of organics-phase loading iron indicates that the iron ions were uniformly distributed as the rod-like polymers in both organic and water phases, the emulsion became serious with the increasing of iron ion polymerization. The further FT-IR. analysis manifests that the mechanism of the cation exchange and solvation were both existed in the saponification P507extraction process; the content of loading iron ions plays a significant effect on rare earth extraction, the exatraction of iron was prior to rare earth and reduces the extraction product of rare earth, when being serious, it will cause emulsion in organic phase.