This paper studied the selective extraction of light rare earth ions from complex sulfate systems with multiple-ions coexistence using aza-crown ether(2N15C5).The results show that high concentration impurity ions in the aqueous phase mainly affect the stability of complex sulfate system by inducing the precipitation of rare earth sulfate sodium salt,thereby reducing the selectivity and distribution ratio of 2N15C5 for light rare earth ions.Under the conditions of pH＜2.0,[SO2-4]/Σ[RE3+]＜10 in aqueous phase,phase ratio RO/A=2∶1,mixing time of 10 min and coexistence of multiple impurity cations,the single-stage extraction coefficient of light rare earth ion group and heavy rare earth ion group can reach 23.0023,and the corresponding cumulative extraction coefficient after 5-stage counter-current extraction can reach 36.7016.This grouped-extraction method can selectively extract low-concentration light rare earth ions from the in-suit leaching tailing liquid of ion-adsorbed rare earth ores.The enriched light rare earth solution can be obtained from the loaded organic phase by washing with dilute hydrochloric acid and anti-extracting with ethylenediaminetetraacetic acid(HEDTA)solution.The overall recovery rate of light rare earth ions is 83.98%.
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