Design Of A Novel Membrane Emulsification Circulation Extractor And Its Application

Solvent extraction is an important method for purification and separation in pertrochemical,hydrometallurgy,nuclear chemical industry and biopharmaceutical.Although some conventional extractors like mixer-settler,extraction columns and centrifugal extractor have developed mature,the mass transfer of these extraction devices is poor.To solve this problem,an extractor which can achieve a fast and fully mixed two-phase is necessary.However,the better the two phases are mixed,the easier it becomes to emulsify and difficult to separate from each other.So in this work,we develop a membrane emulsification circulation(MEC)extractor which can achieve high extraction performance and fast phase separation simultaneously.The membrane emulsification extractor designed in this thesis can achieve thorough mixing of organic and aqueous phases by the dispersion of porous membrane.Rapid phase separation can be achieved by the design of the extractor structure.The effects of some parameters on the extraction performance of the equipment are systematically investigated.The application of the extractor in the extraction of percious metals and the separation of actinium from rare earth elements is also studied.The main results and innovation spots in this study are as follows:1.An extractor(MEC extractor)with good performance of extraction and phase separation was designed.Compared to stirring extraction,MEC extraction exhibits faster extraction kinetics of Pd(?)and the phase separation process can be achieved within 20 s.The MEC extractor enables efficient extraction of different concentrations of Pd(?)(0.001 mM?10 mM).Smaller pellet size of the sintered polyethylene membrane and higher flow rate benefit the extraction.In the end,an empirical formula for predicting the residual metal ions concentration in the water phase was developed.3.The application of MEC extractor in the extraction of precious metals was investigated.The efficient extraction of precious metals was achieved with low consumption of organic phase.The effects of diluent and Chci was investigated to get the best experimental conditions.The selective extraction of precious metals from simulated waste electronic components leaching solution was realized by MEC extractor,and the extraction efficiency of precious metals were over 90%.4.The application of MEC extractor in the separation of actinides and lanthanides was investigated.According to the results of batch experiments,the increase of pH and extractant concentration is beneficial to increase the extraction efficiency of U,Th and Eu.The best separation conditions were obtained through the MEC extraction experiments,the effective separation of U,Th and rare earth elements can be achieved with the pH<1.50.U,Th can be separated efficiently in 0.5 M HCl solution during stripping process.Finally,the experimental procedure for separating U and Th from rare earth elements using MEC extractor was given.