Abstract: Comparative studies on the extraction of Cu(Ⅱ) have been performed by 2-hydroxy-5-(1-methylheptyl) benzaldoxime (N-590) without or with n-dodecanol as modifier, 2-hydroxy-5-(1-metylheptyl) benzophenone oxime (N-510), and 2-hydroxy-4-(1-methylheptyloxy) ben-zophenone oxime (N-530).When the extraction is carried out in feed liquor containing Cu 1.03 g/L and Fe 10.7 g/L by 0.1 mol·dm^-3 extractant in kerosene, the Cu percentage extrac-tion of 95.6, 89 and 63%, and Cu(Ⅱ)-Fe(Ⅲ) separation factor of 1.46×10³, 4.76×10²and 1.26×10² are obtained with N-590, N-530 and N-510, respectively; moreover the Cuextraction and stripping speed with N-590 is greatly higher than that with N-530 and N-510.Addition of 2% n-dodecanol into 0.1 mol·dm^-3 N-590 in kerosene improved the strip-ping behaviour.

Key words: hydroxy methylheptyl benzaldoxime, hydroxy methylheptyl benzophenone oxime, hydroxy methylheptyloxy benzophenone oxime, extrcation, Cu(Ⅲ)