Kinetic study of lithium extraction from solution with iron-based ionic liquid system
In this paper,tributyl phosphate(TBP)was used as an extractant,1,2-dichloroethane(C2H4Cl2)was used as a diluent,and the iron-based ionic liquid 1-butyl-3-methylimidazole iron tetrachloride([C4mim][FeCl4])was used as a co-extractant to construct TBP-[C4mim][FeCl4]-C2H4Cl2 extraction system.The kinetic process of lithium extraction from solu-tion by TBP-[C4mim][FeCl4]-C2H4Cl2 system was studied by constant interface cell method.The effects of volume fraction of ionic liquid,concentration of lithium in aqueous phase,interface area,stirring rate and temperature on the extraction rate were investigated by single factor experiment.The results showed that the extraction reaction rate could be increased by in-creasing stirring rate,interface area and temperature.The extraction reaction of Li+by TBP-[C4mim][FeCl4]-C2H4Cl2 sys-tem mainly occurred at the phase interface.The apparent activation energy was Ea=10.68 kJ/mol and the extraction process of lithium was controlled by diffusion.The kinetic equation of the extraction system was obtained by linear fitting:R2(Li)=1.221×10-2c(Li+)1.347φ(FeCl-4)0.474φ(TBP)1.877.The reaction order of Li+concentration,FeCl4-concentration and TBP con-centration was close to 1,0.5 and 2,respectively.The effect of these three factors on the reaction rate was in the descending order:TBP,Li+,FeCl4-.This study provided some guidance and reference for in-depth understanding of the mass transfer mechanism and reaction control mode in the process of lithium extraction by ionic liquid system.
iron-based ionic liquidkineticsconstant interface cellextraction of lithium
NETL
NSTL
万方数据
