In present research, a new chelating collector S-carboxymethyl-O, O'-dibutyl dithiophosphate (CMDT) was used in the flotation separation of malachite from quartz. The flotation performances of CMDT on malachite (Cu2CO3 (OH)(2) and quartz (SiO2) were evaluated by micro-flotation tests. The flotation results demonstrated that CMDT exhibited a stronger adsorption and a better selectivity on malachite against quartz. A good separation efficiency for artificially mixed minerals was obtained at pH around 9.0 with Na2S as a regulator together. The CMDT adsorption mechanism was investigated and analysed by Fourier transform infrared spectroscopy (FT-IR), zeta potential and X-ray Photoelectron Spectroscopy (XPS) analysis. The FT-IR spectra showed that CMDT could react with Cu2+ ions and might adsorb on malachite surface by strong che misorpt ion. On the other hand, zeta potential and XPS analysis results provided enough evidences that CMDT possessed a stronger affinity on malachite than quartz. (C) 2020 Published by Elsevier B.V.