Abstract: STUDY ON SYNERGISTIC EXTRACTION OF RARE EARTH ELEMENTS WITH HBTMPTP AND HPMBPKong Wei Li Deqian(Laboratory of Rare Earth Chemistry and Physics,Changchun Institute of Applied Chemistry,the ChineseAcademy of Sciences ,Changchun 130022)Zhang Xiuying Wang Chaomin(Department of Chemistry,He'nan NormalUniversity,Xinxiang 453002)ABSTRACTThe synergistic extraction of rare earth elements from aqueous nitric acid with benzene solutions of bis(2,4,4trimethylpentyl)monothiophosphinic acid (HBTMPTP,HL) and 1phenyl3methyl4benzoylpyrazolone5 (HPMBP,HA) has been studied.The composition of the extracted complex of La(Ⅲ) has been determined to be LaNO3·HL2·A·2HA by slope analysis and IR spectrophotometer analysis.The equilibrium constants have also been calculated.Key words Synergistic extraction Rare earths HBTMPTP HPMBP