The synergetic depression effect of KMnO4 and CMC on the depression of galena flotation

The mechanism of carboxymethyl cellulose (CMC) on the galena surface and the enhancement of KMnO4 on the depression of CMC to galena were investigated by flotation test, surface adsorption experiments, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and X-ray photoelectron spectroscopy (XPS). Flotation test results indicated that the addition of KMnO4 under alkaline condition significantly enhanced the depression effect of CMC on galena. Surface adsorption experiments of butyl xanthate (BX) and CMC demonstrated that the adsorption amount of BX decreased after CMC was added into the pulp. And the adsorption amount of CMC increased while BX decreased sharply when KMnO4 was added into the pulp. After galena was treated with KMnO4 and CMC, dim spots (oxidation sites) on the surface of galena were observed by SEM-EDS. Results showed the high contents of C and O on the oxidation sites. XPS results indicated that oxidation-reduction reaction occurred on the mineral surface, and PbS2O3 or Pb(OH)2 was probably the main component of the oxidization sites. The CMC could be adsorbed on the oxidation sites by the hydrogen bond to form a hydrophilic membrane on the mineral surface lead to galena depression. All results showed that KMnO4 could enhance the depression effect of CMC on galena.