Abstract:One step transition process was frequently used in transformation of infusion through P507, but content of non-rare earth impurity in mixed rare earth chloride was higher. Mixed rare earth chloride was prepared by simulation of countercurrent cascade extraction, and changes of content of non-rare earth impurity in reverse extraction solution were investigated. The results show that contents of Mn4+, Zn2+, SO42-, Mg2+ and Ca2+ in extraction solution drop by more than 50% compared with original extraction process under the conditions including extraction mixing time of 9 min above, pH value of extraction solution of 4, pH value of acidity of washing solution of 1.5, stripping volume ratio of 20, and extraction solution of 6 mol/L.