Abstract: The flotation separation of galena, sphalerite, and pyrrhotite was investigated with CCSL as a depressant. Flotation test results show that galena and sphalerite can float but pyrrhotite can barely float with CCSL as a depressant. The flotation tests also show that galena can be separated efficiently from pyrrhotite, and that sphalerite can be separated on the whole from pyrrhotite, but the separation efficiency of the former is much better. The X-ray photoelectron spectroscopy (XPS), IR spectrum, and Zeta potential analysis results indicate that the interaction of sodium acetate and pyrrhotite is not only physical absorption. The UV spectrum indicates that the decline in floatability of pyrrhotite is due to the hydrophilicity caused by CH₃COO^- being stronger than that caused by dixanthogen, and the xanthate adsorption on pyrrhotite is not prohibited by CH₃COO^-. The CH₃COO^- reacts not only with pyrrhotite, but also with H⁺ in water as a H-bond, so the pyrrhotite becomes hydrophilic.