Abstract: The floatability of Galena，Sphalerite and monoclinic Pyrrhotite in different pH and different potential with DDTC as collector were studied.It showed that Galena could float well in the whole pH tests，the floatability of monoclinic Pyrrhotite became low under low pH，and the floatability of Sphalerite decreased greatly with pH increased; The variety of potential insensitively affected on monoclinic Pyrrhotite，the floatability of galena decreased with the increase of potential，and the floatability of Sphalerite became low with the decrease of potential.  

Key words: DDTC, Galena, Sphalerite, Monoclinic Pyrrhotite, Electrochemical floatation